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EU4 - Development Diary - 26th of March 2019

Good day and welcome to this week's Dev Diary for EUIV. I'm sure it comes at an unforgivable late hour for many, but I have not long returned from a short trip to Lithuania. The country is a bit smaller than I remember, but Vilnius was a delightful place to spend the long weekend.

I'm returning as forewarned by last week's Dev Diary to talk about ambitions for game mechanics in the upcoming European Expansion, slated for Q4 this year. As neondt has been discussing with maps and missions, I too will be sharing thoughts and ideas that we have regarding certain game mechanics. What is mentioned here are not changes that are currently in the game, nor are they promises of things to come, but more to share our thought process and ideas we have for the upcoming expansion and update.

During the large end of year Dev Diary I mentioned various wishlist items that we would like to tackle in EUIV and on the list, right at the top, which with a degree of imagination is in bold, flashing colours and on fire, is that the current state of mercenaries in the game is long overdue for a shakeup. That's what we're here to talk about today.

Firstly, why are we even talking about Mercenaries at all? Well Europa Universalis is a game about building Empires, and the business end of your stick are your armies. While regular armies are cost-effective for ducats, they can and likely will run dry of manpower in prolonged wars. Mercenaries exist for you to supplement your fighting force at an inflated ducat cost, allowing you to extend your own fighting capacity so long as your coffers can handle it. In the past, there was a limit to how many mercenaries were available to hire due to a 1% daily chance of mercs becoming available. This was removed in the interest of expunging the random element to available armies, and now your number of available mercs are tied to your forcelimit. Mechanically it's all very functional, but not without its issues

40-0-40 mercs.jpg


Look familiar? Once one's economy is in good shape, the go-to for a nation is to flesh out their army mercenary infantry and, should they feel decadent, mercenary artillery and keep that as a permanent solution for all aspects of warfare. They are the ultimate siege weapon due to reinforcing without need for manpower, so attrition is seldom a concern, while also being an entirely effective battle force as they take your nation's bonuses to battle, and any losses are very quickly recovered in exchange for money.

Even in the event of your mercenary armies being wiped out, so long as you have the money, you are able to swiftly recruit as far as your force limit allows courtesy of their quick recruitment time, and within a few months, your armies march once more with renewed vigour and no impact on your manpower pool.

Now to its credit, the way mercenaries work currently allows for a nation to always keep their momentum going. It can be no fun to simply sit on your thumb for manpower to recover for a war you want to fight if you find no other options available to you, and I'm sure most of us have found ourselves in a war which would have been all but lost if a few loans and an eager band of mercenaries had not been available to save the day.

So what are our thoughts from here? Well, there is certainly no end to the balance tweaking that could be done here, as the variables involved are plenty and could be adjusted: rising cost of mercs, restricting their availability, perhaps reigning in how easily they adapt to all of your country's military traditions, fostered for centuries, within a few days. This could be done, and indeed it wasn't too long ago that we did increase mercenary costs across the board, but I believe the solution should be grander in ambition, to be fitting for the gravity of the Expansion we're planning for this year.

@Groogy and I have hashed out thoughts on mercs with very much a "back to the drawing board" approach on the system. What has become more and more apparent is that the system as it exists is ripe for a full makeover.

The European Expansion and its update will, in all likelihood, feature a completely different mercenary mechanic from what we know today. We have established several key aspects of how we want to handle mercenaries:

  • We still want them to exist as a way to supplement one's army strength for ducats.
  • Province-level recruitment will probably have to go. Reducing click-fatigue while we're at it should be a priority.
  • The system should respect geopolitics: Mercs in India should be functionally different from Germanic ones.
  • Mercs must be finite to some degree. As an example, a prolonged 30 years war should drain Central Europe of available mercenaries, and said merc units should find themselves no longer able to reinforce.
  • Player involvement in the system must be greater than it is today
  • Late game multiplayer must be diversified from all out merc-on-merc warfare.
  • The system should be robust, feel alive, and enjoyable

In addition to this, we want to make the fundamental changes to the merc system part of the update. All players who get the planned Q4 update should enjoy a new merc system to explore.

The Dev Diary may end up raising more questions than it answers regarding mercs, but this is not the last we'll be talking on the matter. This and various other DDs to follow are to shed light on our internal thoughts regarding development, rather than showing off what we have added to the game. I'm sure you're growing tired of hearing it by now, but we continue to iron out tech-debt issues (which really deserve a dev diary of their own) and gearing ourselves up for developing this large European Expansion.

What are your thoughts on the existing mercenary system and what would you like to see in a new update? Let us know in this thread, and we'll be back next week to talk more on our plans for the upcoming Q4 Expansion and Update
 
Right, but the result is a pool that is exclusive to you. The two things this lacks are a sense of competition for scarce resources and any effect on the availability of the said resources caused by local wars. Both elements should, I think, be a feature of a good mercenary system.

There is competition for the mercenaries in the same way there is competition for the trade value. One of the major drawbacks to a system like the one you proposed is that, as soon as you discover a node, you could just pause the game and buy out all of the mercenaries, leaving the AI with none, unless you restrict the hiring by some arbitrary means. (But if you use some means to restrict hiring, you don't need the manpower pool.) That is something that should not be possible. Nations that have no established economic presence in a region should have a more difficult time building trust and establishing payment routines with contacts in the region. This is why I think its important for mercenary recruitment to be tied to an envoy (in this case, a Merchant) and there needs to be competition for the number of mercenaries available, but that competition needs to be represented by something other than a manpower pool for mercenaries that every country hires from.

A shared manpower pool doesn't create a competition because the AI cannot act while the game is paused and the player can, and in multiplayer all it causes it click fatigue. Having a shared manpower pool for mercenaries isn't actually different for a player than the current "available mercenaries" cap except that it requires a lot more clicks to use.

Okay, but my point was that hiring mercenaries in a node doesn't affect the mercenaries available to any other country in the node

The amount of trade power that you have in the node affects the available mercenaries for other nations. It is dynamic. It is competitive.

Right, but the result is a pool that is exclusive to you.

But if your pool increases, someone elses decreases. That's the way it works. When you have mercenaries, you have taken them from a "shared pool" (the cap the node calculates) using your trade power. If you increase your trade power to increase your cap, everyone else's cap is lower. You stole their mercenaries.

Let's take the calculation I did earlier as an example. Right now Spain gets 36, France gets 24, and Genoa gets 16. But now Tuscany has turned on his slider so he's using his 18% trade power to compete. That gives us a new ratio of 37, 25.5, 16, and 18. With this new ratio Spain has a cap of 29 units, France has a cap of 20 units, Genoa gets 12 units, and Tuscany gets 15. Tuscany took 15 units from the other nations. But Tuscany can't just decide to hire all the mercenaries even if he has the cash to do so because the Spanish, French, and Genoese have long-established contacts and loyalties and, most importantly, are also actively hiring. Given the ongoing recruitment campaigns by other nations, 15 units of mercenaries is the best Tuscany's agents could do.

As for war: occupation reduces trade power. So if, say, Austria-Hungary is occupied by the Ottomans for several years, they will have less trade power in Venice, Ragusa, etc, which means that every other nation actively recruiting mercenaries in those nodes see a relative increase to their capacity. But, at the same time, devastation reduces trade value, so if the war dragged on there would be less total units in the node.

This has the side effect of preventing nations that are losing badly from spamming kamikaze merc stacks, and making blockades more important for winning large wars, since blockades affect trade power.
 
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Following up on the April 2 dev Diary
A Unique Mercenary estate that grants various positive/negative buffs based on there loyalty/influence in your country. Personally I would hate to dish out land to these Warriors for Hire when really there just out to line there pockets with an honest trade but I could see the use in helping balance out Merc Spams across the map. Just a few ideas I can jot down would be
-Loyalty effects cost
-Loyalty ticks up with your power projection being high
-High Influence effecting how good you're Mercenaries Fight
-Influence ticks up with standing Merc Armies
-If for example your armies were to increase in cost as they fought further and further from your capital home region maybe we could see permanent standing Mercenaries fighting out in the farther frontiers of your empire like your colonial trade regions while keeping your boys to defend the homeland
-Unique Mercenary Estates (Looking at you Switzerland)
-Disasters and monetarily costly events
I'm kind of just letting out some ideas as to what bartering with these guys would look like, but let me know if you guys like/hate the idea or if more could be added to make it done better
 
There is competition for the mercenaries in the same way there is competition for the trade value. One of the major drawbacks to a system like the one you proposed is that, as soon as you discover a node, you could just pause the game and buy out all of the mercenaries, leaving the AI with none, unless you restrict the hiring by some arbitrary means. (But if you use some means to restrict hiring, you don't need the manpower pool.) That is something that should not be possible. Nations that have no established economic presence in a region should have a more difficult time building trust and establishing payment routines with contacts in the region. This is why I think its important for mercenary recruitment to be tied to an envoy (in this case, a Merchant) and there needs to be competition for the number of mercenaries available, but that competition needs to be represented by something other than a manpower pool for mercenaries that every country hires from.
I don't disagree with the need for some limitations around trust and affinity, but I just don't see units that are waiting to be hired by just one country as "mercenaries". I'm thinking, rather, that you turn the idea around; that there is a proportion of mercenaries in any node that won't agree to sign for a particular country. This prevents any one country from buying up all of the mercenaries in a node, but means that there is overall competition for them. In a given node with, say, 20 mercenary units, around 7 or so would be unavailable to each country - the exact proportion being affected by past actions, trade power, policies and so on. Any one country can't hire up all units in the node, but two countries between them might.

A shared manpower pool doesn't create a competition because the AI cannot act while the game is paused and the player can, and in multiplayer all it causes it click fatigue. Having a shared manpower pool for mercenaries isn't actually different for a player than the current "available mercenaries" cap except that it requires a lot more clicks to use.
Well, that assumes no "unavailability" mechanic and also that the player can afford to hire all the mercenaries in all the nodes they have access to - something that should be out of the question, generally speaking. And the AI can click a lot faster (and with a faster reaction) than any player.

The amount of trade power that you have in the node affects the available mercenaries for other nations. It is dynamic. It is competitive.
What happens if you lose trade power after you hire the mercenaries? If you keep the mercs I can see exploits, here; if you don't then I don't really know what's being represented?

But if your pool increases, someone elses decreases. That's the way it works. When you have mercenaries, you have taken them from a "shared pool" (the cap the node calculates) using your trade power. If you increase your trade power to increase your cap, everyone else's cap is lower. You stole their mercenaries.
Except that you don't even need to hire them to keep them "stolen" - they will wait around in the hope you will hire them rather than take an offered contract, apparently. Also, same question as above: what happens if you "steal" the units while they are already on hire to someone else? Do you disband them from the other country's army for free? Or do they stay but spawn another unit that you could hire, thus overtopping the "cap" on the node?

Let's take the calculation I did earlier as an example. Right now Spain gets 36, France gets 24, and Genoa gets 16. But now Tuscany has turned on his slider so he's using his 18% trade power to compete. That gives us a new ratio of 37, 25.5, 16, and 18. With this new ratio Spain has a cap of 29 units, France has a cap of 20 units, Genoa gets 12 units, and Tuscany gets 15. Tuscany took 15 units from the other nations. But Tuscany can't just decide to hire all the mercenaries even if he has the cash to do so because the Spanish, French, and Genoese have long-established contacts and loyalties and, most importantly, are also actively hiring. Given the ongoing recruitment campaigns by other nations, 15 units of mercenaries is the best Tuscany's agents could do.
How do we know that the other countries are "actively hiring" unless they actually hire? Is this an argument for a "bidding" system - where hiring mercenaries takes time (as now), during which others can outbid you for a portion of your requested contracts? That might well be a good idea (independent of the system for "capping", etc.). If competitive bidders in the node ended up with proportions of the "shared" regiments based on the ratio of prices offered, with up-front hire for a minimum period, that could perhaps work.

Taking the example of a node with 20 total regiments, country A having 7 unavailable, country B having 6 unavailable: country A gets the 6 unavailable to B, country B gets the 7 unavailable to A and the remaining 7 are split according to the ratio of final bids? Maybe that would work?

As for war: occupation reduces trade power. So if, say, Austria-Hungary is occupied by the Ottomans for several years, they will have less trade power in Venice, Ragusa, etc, which means that every other nation actively recruiting mercenaries in those nodes see a relative increase to their capacity. But, at the same time, devastation reduces trade value, so if the war dragged on there would be less total units in the node.
OK, that's an interesting consequence, but unavailable regiments could just as well be inflated by war score against, occupations or trade value.

This has the side effect of preventing nations that are losing badly from spamming kamikaze merc stacks, and making blockades more important for winning large wars, since blockades affect trade power.
Yes, but you could do the same with unavailable regiments rather than having a set number of regiments "on call" for every country. The unavailability could be affected by war score ratios as well as whatever else, if you don't rely on a division of the total 'pool' of regiments according to trade power or some other score. Devastation and regular unit casualties should really lead to more mercenaries, not less, as increasing numbers see no other way to make a living.
 
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but I just don't see units that are waiting to be hired by just one country as "mercenaries".

The units don't exist until some country creates them. The cap (as I proposed) doesn't represent the actual number of units standing around in the market, it represents the theoretical maximum number of recruits a nation could recruit and mobilize given their logistical establishments in a region and their competitors. It's an abstraction.

Except that you don't even need to hire them to keep them "stolen" - they will wait around in the hope you will hire them rather than take an offered contract, apparently. Also, same question as above: what happens if you "steal" the units while they are already on hire to someone else? Do you disband them from the other country's army for free? Or do they stay but spawn another unit that you could hire, thus overtopping the "cap" on the node?

If you have the slider up and are using your trade power to compete in the node, you are paying mercenaries: they arrive in the form of a monthly manpower bonus. The units that you can spawn immediately represent how much of this incoming manpower you can mobilize immediately (again, as a theoretical abstraction.) That's why the units are dependent on the node: they haven't been organized into the employer's army.

Taking the example of a node with 20 total regiments, country A having 7 unavailable, country B having 6 unavailable: country A gets the 6 unavailable to B, country B gets the 7 unavailable to A and the remaining 7 are split according to the ratio of final bids? Maybe that would work?

There is a difference between complexity and strategic depth.

You're talking about a lot of things like keeping track of whether cultures are accepted and by who and where units suffered casualties and how many were disbanded and diplomatic trust issues, etc etc.

But just consider autonomy for a moment. Autonomy lowers the provincial trade power value.

If I'm playing in Italy, and I conquer Genoa, that land will have higher autonomy than it did when Genoa owned it. So if Aragon for instance had trade power in the node, they now have a larger percent of trade power in the node (do the math, it checks out). So Aragon has more mercenaries from Genoa simply because I conquered the land there. How is that actually different than Aragon getting mercenaries because the 4th battalion lost so many men at such battle so they went to find work somewhere else. Either case represents defeated but not quite subjugated Genoans being hired by Aragon.

Also, if they're just added back to the node pool, Genoa or even I could just hire them.

Then consider privateers. They add a block of trade power to the node, reducing the relative share of every other nation in the node, resulting in fewer recruits. This represents prospective mercenaries choosing a life on the high seas rife with rum and venereal diseases.


You don't need to make things fancier than they need to be.

Devastation and regular unit casualties should really lead to more mercenaries, not less, as increasing numbers see no other way to make a living

You can't hire dead people.

In the short term, devastation increases the relative share of mercenaries since it affects trade power. If I'm playing Venice, and Austria gets fully occupied by the Ottomans, Austria will have a lower relative share of the trade power in Vienna because of the devestation, so I could hire more mercenaries. But if Austria stays occupied for 10 years, we would start to run out of Austrians to recruit, at least until we learn how to grow soldiers from the ashen barrens of former cities.
 
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The units don't exist until some country creates them. The cap (as I proposed) doesn't represent the actual number of units standing around in the market, it represents the theoretical maximum number of recruits a nation could recruit and mobilize given their logistical establishments in a region and their competitors. It's an abstraction.
OK, let me put it a different way: after I have hired every single mercenary in the node I possibly could, you will still be able to hire exactly as many as you would have been able to if I had never hired any at all. That does not strike me as a plausible scenario.

If you have the slider up and are using your trade power to compete in the node, you are paying mercenaries: they arrive in the form of a monthly manpower bonus. The units that you can spawn immediately represent how much of this incoming manpower you can mobilize immediately (again, as a theoretical abstraction.) That's why the units are dependent on the node: they haven't been organized into the employer's army.
And, again, whether you actually mobilise any or all of that manpower has no immediate impact whatsoever on how much manpower another country can mobilise in the same node. Nor do wars, demobilisations, casualties or such like have any short-term impact. In those respects, the system does not seem plausible (or particularly interesting, from a gameplay pov).

There is a difference between complexity and strategic depth.

You're talking about a lot of things like keeping track of whether cultures are accepted and by who and where units suffered casualties and how many were disbanded and diplomatic trust issues, etc etc.
Leaving aside that all of those things are already tracked by the game, so no additional tracking would be required, I'm not wedded to the idea of a manpower pool as such, at all. But what I am trying to do is identify what aspects any system ought to respond to; what sorts of system response do we want, rather than starting with a system and seeking justifications for it.

But just consider autonomy for a moment. Autonomy lowers the provincial trade power value.

If I'm playing in Italy, and I conquer Genoa, that land will have higher autonomy than it did when Genoa owned it. So if Aragon for instance had trade power in the node, they now have a larger percent of trade power in the node (do the math, it checks out). So Aragon has more mercenaries from Genoa simply because I conquered the land there. How is that actually different than Aragon getting mercenaries because the 4th battalion lost so many men at such battle so they went to find work somewhere else. Either case represents defeated but not quite subjugated Genoans being hired by Aragon.
But devastation, conquest and the like also affect trade value, which also affects the number of mercenaries in your scheme (but in the opposite way, leading to fewer of them available, overall). The root here is that I don't think trade value is a good basis for the total number of available mercenaries in a node in the short term. It's fine for a long-term equilibrium value, but as Keynes once almost said "in the long-term, we're all dead". Short-term influxes of unemployed but trained soldiers have a much higher impact on mercenary numbers than shifts in trade value or power.

Also, if they're just added back to the node pool, Genoa or even I could just hire them.
Genoa being able to hire soldiers made unemployed by conquest of their own lands seems entirely reasonable, to me (assuming they have the money to do so). You hiring them is not out of the question (they are mercenaries, now, after all!), but if you are less attractive to them then that should be accounted for in the modifiers (from non-accepted cultures and recent conquest, bothe simple, already tracked and used elsewhere in the game).

Then consider privateers. They add a block of trade power to the node, reducing the relative share of every other nation in the node, resulting in fewer recruits. This represents prospective mercenaries choosing a life on the high seas rife with rum and venereal diseases.
Shouldn't that reduce sailors, not mercenary recruits?

You don't need to make things fancier than they need to be.
Indeed - but it's a good idea to work out what they need to achieve before settling on a system, be it a fancy one or a plain one. If a system doesn't meet the need, then it's in need of change, however fancy or plain it is.

You can't hire dead people.
Since you are abstracting and not keeping track of either live or dead people, I don't see how this is relevant. Only around 20% of casualties in early wars are typically "dead people". Another 20% (ish) are hurt so badly that they never fight again, and the rest generally return to the fight after a longer or shorter delay.

In the short term, devastation increases the relative share of mercenaries since it affects trade power. If I'm playing Venice, and Austria gets fully occupied by the Ottomans, Austria will have a lower relative share of the trade power in Vienna because of the devestation, so I could hire more mercenaries. But if Austria stays occupied for 10 years, we would start to run out of Austrians to recruit, at least until we learn how to grow soldiers from the ashen barrens of former cities.
Devastation also affects trade value, reducing the total available number of mercenaries (whereas, in the short term, it should increase them). Again, it would be better to look at dynamic rather than static (or even semi-static) driving forces, I think. What adds to the availability of mercenaries is the increase of devastation, not the devastation itself. Likewise, it's the conquest of new lands that increases aggressive expansion (and aversion of service for some mercenaries) rather than the holding of lots of land. A system based only on trade value and power will never reflect these factors.
 
Devastation also affects trade value, reducing the total available number of mercenaries (whereas, in the short term, it should increase them). Again, it would be better to look at dynamic rather than static (or even semi-static) driving forces, I think.

The reduction in trade value from devestation is a long term effect on the total mercenaries. The short term affects of occupation are to increase the relative trade power of other nations hiring mercenaries in the node by lowering the provincial trade power of the occupied provinces.

Since you are abstracting and not keeping track of either live or dead people, I don't see how this is relevant. Only around 20% of casualties in early wars are typically "dead people". Another 20% (ish) are hurt so badly that they never fight again, and the rest generally return to the fight after a longer or shorter delay.

If all the Austrians are dead because Turkic Mongols have been raiding their lands for several decades, it would be difficult to find any for the armies. In the short term, wars and occupation should increase the relative availability of recruits, but in the long term the population loss from an extended war would lead to a decrease in the total number of troops available. The loss of trade value due to devastation reflects the first point, while the loss of trade power reflects the first.

And, again, whether you actually mobilise any or all of that manpower has no immediate impact whatsoever on how much manpower another country can mobilise in the same node.

OK, let me put it a different way: after I have hired every single mercenary in the node I possibly could, you will still be able to hire exactly as many as you would have been able to if I had never hired any at all. That does not strike me as a plausible scenario.

These things are simply not true of the system I described, so I apologize if I've explained it poorly. Let me try to frame it a different way.

When you slide the slider up to pay money in order to use your money to contract mercenaries in (a) node(s), you start receiving a monthly manpower bonus relative to the trade value in the node and your modified relative share of trade power. Those are the units that you are hiring. If someone else starts using their trade power to hire units, your share of trade power goes down, so you get less units.

The special units, the ones you can spawn that act like what we think of as mercenaries, represent the units that you have already hired but that have not yet been deployed (ie, added to the manpower pool.) They're already paid for, that's what the monetary cost of the slider represents.

Leaving aside that all of those things are already tracked by the game, so no additional tracking would be required,

The game doesn't track the culture of individual units or diplomatic relations for things that aren't nations. Non-accepted culture in provinces grant manpower -33%, so there could be a modifier for mercenary value +33% in provinces with unaccepted cultures, increasing the provincial trade value for calculating mercenaries.

Short-term influxes of unemployed but trained soldiers have a much higher impact on mercenary numbers than shifts in trade value or power.

Right, but those unemployed soldiers would relocate to find work. A soldier that desserts in Africa isn't going to hang around Buganda looking for work. The way that things move in EU4 is represented by the flow of Trade Value. Trade routes with more value are more traveled, so as a matter of statistics more mercenaries would be there simply because there's more of everything there.

Shouldn't that reduce sailors, not mercenary recruits?

The justification for separating sailors from the general manpower pool was already loose at best.

But what I am trying to do is identify what aspects any system ought to respond to; what sorts of system response do we want, rather than starting with a system and seeking justifications for it.

Right, but so far the discussion has been about what level of abstraction is preferable to represent certain historically based ideas of what mercenaries should be like. I was merely trying to illustrate that a more abstract, rather than purely simulationist, representation is also plausible.

But what do we want the system to do?

We want interesting choices. If Mercenaries are a self-contained system dependent only on factors that only affect mercenaries, they can be optimized as a sub-game with little interaction with other choices made in other systems. If mercenaries are tied to consequences that arise from other systems, it creates interesting choices in the way those system connect.

We want player involvement. Choices made by the player should be impactful to their overall strategic goals. If the mercenary system is dependent on something that is outside the player's control, it's not any more strategically meaningful than a dice roll.

We want the system to be dynamic. Diplomatic and military actions should change the availability and distribution as the game progresses.

And most of all, we want a system that can be understood and responds predictably. In a strategy game, a player should be able to know to some degree of confidence in advance how their actions affect the grand scheme of things. Otherwise, it's less of a strategy and more of a gamble.

The features as you proposed do a better job of simulating the aspects of individual mercenaries, but it relies on factors the player is incapable of influencing or planning for, it utilizes information that is impossible to convey to the player reasonably, its isolated from other systems creating the need for unique modifiers and modifier-modifiers to have any choice at all, and it requires the player to constantly pause and check values which have a large impact on their military capability but which change periodically and essentially randomly based on factors the player cannot control, predict, or realistically be notified of (which may be more true to life, but that doesn't make a system strategically interesting).
 
The reduction in trade value from devestation is a long term effect on the total mercenaries. The short term affects of occupation are to increase the relative trade power of other nations hiring mercenaries in the node by lowering the provincial trade power of the occupied provinces.
But increasing the trade power proportion does not increase the total number of mercenaries available, at all - that is my point. The total cap on the node hasn't changed at all.

If all the Austrians are dead because Turkic Mongols have been raiding their lands for several decades, it would be difficult to find any for the armies. In the short term, wars and occupation should increase the relative availability of recruits, but in the long term the population loss from an extended war would lead to a decrease in the total number of troops available. The loss of trade value due to devastation reflects the first point, while the loss of trade power reflects the first.
I would expect "all Austrians being dead" to be reflected in the manpower development of the area, not just transiant factors! It takes a hell of a lot, even in later periods, never mind early-modern, to depopulate a whole area.

These things are simply not true of the system I described, so I apologize if I've explained it poorly. Let me try to frame it a different way.

When you slide the slider up to pay money in order to use your money to contract mercenaries in (a) node(s), you start receiving a monthly manpower bonus relative to the trade value in the node and your modified relative share of trade power. Those are the units that you are hiring. If someone else starts using their trade power to hire units, your share of trade power goes down, so you get less units.
Aha - click! This is something I hadn't realised, before; you are using the slider as a "bidding" mechanism, rather than a longer-term policy instrument - and I think I quite like this approach. I think it raises questions regarding what happens once mercenary units from the node are hired, but otherwise it works as an abstraction representing retainer payments, etc. The main question I see is: why not hire out all the units and then set your slider to zero (to get the cash instead of the manpower)? And what happens when you do that, since everyone else's trade power proportion will go up?

The special units, the ones you can spawn that act like what we think of as mercenaries, represent the units that you have already hired but that have not yet been deployed (ie, added to the manpower pool.) They're already paid for, that's what the monetary cost of the slider represents.
Oh, I thought the money cost was the signing bonus (expected and traditional) paid to those joining your manpower pool, but I guess retainers and option contracts could be included, too.

The game doesn't track the culture of individual units or diplomatic relations for things that aren't nations. Non-accepted culture in provinces grant manpower -33%, so there could be a modifier for mercenary value +33% in provinces with unaccepted cultures, increasing the provincial trade value for calculating mercenaries.
You don't need to track anything, other than for countries, I don't think. It's the effect these factors have on the proportion of the pool of mercenaries available to a specific country that matters; the factors are associated with the country, not the trade node.

As you say, provinces with non-accepted cultures could (and arguably should) have a contribution to mercenaries slightly different to their base trade value; but, if you track this, you are effectively tracking a separate value in the node that performs the same function as a putative manpower pool for the node... Basically, all I am saying is that you really need some sort of total for the node that is separate from the basic trade value. What you call this value, or how you represent it, is secondary (and quite malleable).

Right, but those unemployed soldiers would relocate to find work. A soldier that desserts in Africa isn't going to hang around Buganda looking for work. The way that things move in EU4 is represented by the flow of Trade Value. Trade routes with more value are more traveled, so as a matter of statistics more mercenaries would be there simply because there's more of everything there.
Seldom the case, actually - at least until very late in the EU period. The deserters would tend to seek employment quite close to where they deserted, not least because travel could be expensive. Some even returned home and attempted to carry on civilian lives (and several were caught there doing so!) Employment by other governments in the same or a related war was fairly common. Employment in local wars that started after the war in which they were disbanded/deserted was even more common.

The justification for separating sailors from the general manpower pool was already loose at best.
This I don't agree with at all. The skills of a trained soldier and a seaman are very different; the press used by the RN wouldn't have been necessary if it had been desirable to simply put all military recruits aboard ship. There's a reason that non-sailors are referred to on board as "lubbers" and "landsmen" - it's because they're pretty useless there until they are trained up! Attempts to use sailors as troops on land, on the other hand, were generally failures. (The French revolutionary armies tried it, and the British in Egypt likewise - to no great success. Later use of sailors as artillerymen - with naval guns - in 1882 worked fairly well, but that's really out of period). In 'manpower' and 'sailors' we basically have pools of those trained for war on land (reservists, militia, depot units) and those trained to the sea.

Right, but so far the discussion has been about what level of abstraction is preferable to represent certain historically based ideas of what mercenaries should be like. I was merely trying to illustrate that a more abstract, rather than purely simulationist, representation is also plausible.
I don't thin I have ever thought that a purely "simulationist" system would be either practical or desirable. But the system ought to be at least plausible, and reflect common-sense influences on the availability and costs of mercenaries; otherwise, why bother with a supposed historical setting at all?

But what do we want the system to do?

We want interesting choices. If Mercenaries are a self-contained system dependent only on factors that only affect mercenaries, they can be optimized as a sub-game with little interaction with other choices made in other systems. If mercenaries are tied to consequences that arise from other systems, it creates interesting choices in the way those system connect.
Agreed - the mercenaries' availability and cost are affected by a selection of other factors that can be observed and affected (to a degree).

We want player involvement. Choices made by the player should be impactful to their overall strategic goals. If the mercenary system is dependent on something that is outside the player's control, it's not any more strategically meaningful than a dice roll.
They should be impacted by player choices and choices of other countries that can be observed by the player. This is important - part of the game play is reacting to changing circumstances; to do that, (i) the circumstances must be subject to change independent of the player and (ii) those changes must be transparent to the player. The only time it becomes "not any more strategically meaningful than a dice roll" is when the relevant factors are not visible to the player. Things like "are my neighbours at war?" and "has my neighbour just disbanded half his army?" ought to be quite obvious and worth tracking. So should the fact of non-accepted cultures in both your own and others' land.

We want the system to be dynamic. Diplomatic and military actions should change the availability and distribution as the game progresses.
Yes - both in terms of the total number and availability of mercenaries, and of their cost.

And most of all, we want a system that can be understood and responds predictably. In a strategy game, a player should be able to know to some degree of confidence in advance how their actions affect the grand scheme of things. Otherwise, it's less of a strategy and more of a gamble.
Agreed - and the fact of other, similar actions, by other countries, should likewise be clear and visible, even though not directly controlled by the player.

The features as you proposed do a better job of simulating the aspects of individual mercenaries, but it relies on factors the player is incapable of influencing or planning for, it utilizes information that is impossible to convey to the player reasonably, its isolated from other systems creating the need for unique modifiers and modifier-modifiers to have any choice at all, and it requires the player to constantly pause and check values which have a large impact on their military capability but which change periodically and essentially randomly based on factors the player cannot control, predict, or realistically be notified of (which may be more true to life, but that doesn't make a system strategically interesting).
I honestly don't think that there is that much difference between the systems we are envisaging. Both have manpower and mercenary units available for cash via trade nodes (or direct covery contact) in numbers that are limited in total and apportioned according to relative "hiring power". The only thing I am arguing is that I don't think that trade value and power on their own can do a credible or practical job of controlling the availability of the mercenaries. Some additional, transparent modifiers are needed, both for dynamic short-term influences and for political factors affecting mercenary demands. These factors would be linked to countries, states and provinces, and to recent events in local wars and armies. The existence of dynamic effects may well mean that separate totals need to be tracked in the trade nodes, but only one per node (call it "mercenary power"), because it would be subject to dynamic change but then regress back to an "equilibrium value" set by longer-term factors over time.
 
But increasing the trade power proportion does not increase the total number of mercenaries available, at all - that is my point. The total cap on the node hasn't changed at all.

This can be handled with a triggered event that temporarily increases the capacity.

They should be impacted by player choices and choices of other countries that can be observed by the player. This is important - part of the game play is reacting to changing circumstances; to do that, (i) the circumstances must be subject to change independent of the player and (ii) those changes must be transparent to the player. The only time it becomes "not any more strategically meaningful than a dice roll" is when the relevant factors are not visible to the player. Things like "are my neighbours at war?" and "has my neighbour just disbanded half his army?" ought to be quite obvious and worth tracking. So should the fact of non-accepted cultures in both your own and others' land.

Without infiltrating the administration, it isn't possible for the player (or the AI) to know how many casualties are being inflicted, and seeing units disbanded requires compulsive ledger checking. Additionally, the only way to know the affect those actions had on the availability of mercenaries is to compulsively check nodes, but if the AI is scripted with knowledge of how to use the nodes, then the player will never beat them, however if the nodes update on a specific day, the player can pause and utilize the nodes before the AI takes any actions.

They should be impacted by player choices and choices of other countries that can be observed by the player. This is important - part of the game play is reacting to changing circumstances; to do that, (i) the circumstances must be subject to change independent of the player and (ii) those changes must be transparent to the player.

The player can't control whether the AI changes its slider settings or upgrades its centers of trade to gain more trade power, but they can see that clearly and its simple to understand where the change came from. Unless they have Espionage ideas and a lot of spies, it generally won't be possible for the player to know when there's a large battle in the region of a node, and it won't be possible to react to such an occurrence without a notification, like an event popup. However, if there's going to be an event popup, you didn't need to go through the trouble of adding in the system that adds a percentage of casualties to the node: you can just have the event increase the node cap for a short duration.

I honestly don't think that there is that much difference between the systems we are envisaging. Both have manpower and mercenary units available for cash via trade nodes (or direct covery contact) in numbers that are limited in total and apportioned according to relative "hiring power". The only thing I am arguing is that I don't think that trade value and power on their own can do a credible or practical job of controlling the availability of the mercenaries.

I agree with this with one caveat: I don't think that trade value and power on their own in a vacuum can do a credible or practical job of controlling the availability of the mercenaries. If you account for all the systems that currently interact with trade value and trade power, those current systems can be tweaked to allow for a mercenary system where the final calculation only depends on those two variables. For instances, having events following particularly bloody battles and sieges, or slight variants to the way manpower penalties from trade companies, cultural or religious intolerance, and autonomy works (-75% manpower? Sounds like 75% more mercenary value to me). You could have diplomatic reputation affect the slider price scale. You could have espionage actions that reduce a country's mercenary recruitment. But, at the end of the day, you're really only affecting two highly visible factors: Trade Value (as modified by some "mercenary value" scalars) and Trade Power (as modified by some "mercenary power" scalars). Anything you want to do with mercenaries after that can be represented by some combinations of modifiers to those two values because those two values determine the entirety of the mercenary system.
 
This can be handled with a triggered event that temporarily increases the capacity.
That would be a clunky way to do it, but practical. I think a better way would be a value that decays to a neutral value - like prestige does.

The player can't control whether the AI changes its slider settings or upgrades its centers of trade to gain more trade power, but they can see that clearly and its simple to understand where the change came from. Unless they have Espionage ideas and a lot of spies, it generally won't be possible for the player to know when there's a large battle in the region of a node, and it won't be possible to react to such an occurrence without a notification, like an event popup. However, if there's going to be an event popup, you didn't need to go through the trouble of adding in the system that adds a percentage of casualties to the node: you can just have the event increase the node cap for a short duration.
If news of large battles and wars doesn't propagate, if news of mass disbanding is not clear to neighbouring countries, surely that is a flaw in the game? If the largest battle in history has happened just a state away, everyone and his or her dog - never mind the ruler and court - should soon know about it!

I agree with this with one caveat: I don't think that trade value and power on their own in a vacuum can do a credible or practical job of controlling the availability of the mercenaries. If you account for all the systems that currently interact with trade value and trade power, those current systems can be tweaked to allow for a mercenary system where the final calculation only depends on those two variables. For instances, having events following particularly bloody battles and sieges, or slight variants to the way manpower penalties from trade companies, cultural or religious intolerance, and autonomy works (-75% manpower? Sounds like 75% more mercenary value to me). You could have diplomatic reputation affect the slider price scale. You could have espionage actions that reduce a country's mercenary recruitment. But, at the end of the day, you're really only affecting two highly visible factors: Trade Value (as modified by some "mercenary value" scalars) and Trade Power (as modified by some "mercenary power" scalars). Anything you want to do with mercenaries after that can be represented by some combinations of modifiers to those two values because those two values determine the entirety of the mercenary system.
Whether you keep the values as trade value and trade power plus a scaling factor for each, or simply a separate value that is affected by trade value and trade power, is pretty much an academic point. You have four values there to keep; how you arrange them and how you display them is a matter for coders and UI designers to sort out for best efficiency. So, yes, I think there is basically a system there for the building.
 
O.k., let's add a few ideas what could be done with mercenaries even if not completely reworking them. Maybe one or two ideas might prove valuable...

  • in EUIV all land units have pips, in particular morale damage and morale defense pips. How about reducing the morale defense pips of merc units by 1, then, to represent that they will lower the flag more readily than regulars? In early game there are still unit types that do not even have any morale defense pips (wiki is down so can't look these up...), hence mercs will be of equal quality as regulars (in regards to pips). Later on, however, they will be slightly worse than regulars, but can still make a difference for conserving manpower.
  • there seems to be a consensus between players that drilling and professionalism could in theory be an alternative to mercs, but just doesn't do the trick if considered closely re optimal gameplay (I still enjoy the mechanic, though). So why not heap a vfew more modifiers on to it? These could be:
    • 33% of all enemy mercenaries you kill are returned to your own manpower pool - represents the practice to integrate captured mercs into one's own army (they would be ok with that, since they do not have allegiance). Scaling from 0% to 100% professionalism. So the more mercs your enemy has and the more professionalism you yourself have, the better for you (i.e. your manpower pool). This would actually split mercs' main advantage (manpower conservation) between both sides.
    • did you ever wonder why all the soldiers you loose during a battle seem to have been killed instead a portion of them just, you know, having been separated from the main force, running away and joining your forces again later? Thus, at 60% professionalism, we could have another (fixed, non-scaling) modifier that basically returns e.g. 15% of regular soldiers lost in battle to our manpower pool. Probably, however, reinforcement rate should be reduced, then, which brings me to
    • why not have a modifier scaling from 50% to 100% professionalism, this could be +15% reinforcement rate, -15% attrition, or even the above described "captured merc integration"... well, you name it!
    • at some level of professionalism, make it possible to directly create a regular regiment from a merc regiment (i.e. without having to dissolve the mercs and having to pay ducats and manpower to recruit the regulars). This might only be done during peace time, however.
    • The modifier we receive at 80% professionalism (-50% morale damage for reserves) seems a bit lackluster. Why not bolster this with a -50% drill decay modifier? So drill might not be instantly lost after the first battle. Alltogether, regulars might then become more valuable than mercs even for optimizers.
  • Have you ever wondered why we can decrease maintenance of mercenaries? Shouldn't they be extremely unhappy if they do not receive the pay they were promised? Why not lock their maintenance at 100%, then? (like a drilling regular army)
  • ...
 
Have you ever wondered why we can decrease maintenance of mercenaries? Shouldn't they be extremely unhappy if they do not receive the pay they were promised? Why not lock their maintenance at 100%, then? (like a drilling regular army)
Although I never lower my Army Maintenance slider, I like this idea.
 
Yes!

I'm hoping for a revamping of armies in general, with more variety of special units and options for types of drilling for buffs. Or pretty much anything that would make armies more customizable and fun to messy around with.

A merc revamp could tie together with this. I like the idea of CK2 style mercenary companies that get depleted. Those units could have specialties, like sieging or mountainous warfare. Pricing could have malus-bonus scaling based on religion, AE, war score, manpower depletion, and other factors.
 
Yes!

I'm hoping for a revamping of armies in general, with more variety of special units and options for types of drilling for buffs. Or pretty much anything that would make armies more customizable and fun to messy around with.

I would like to see a way to design regiments so that you can customize the bonus you get from Army Drill. For instance you might choose to have your artillery gain extra fire damage when defending on defensive terrain or have a bonus against forts, or have your infantry take less shock damage vs deal more fire damage.

Higher professionalism could unlock new bonuses and make existing bonuses more powerful.

It would be nice if cavalry had really powerful and unique bonuses, like attrition reduction for all units or increased movement speed for all units, or increased sight on the map.
 
Merc's should be organised and brought in bulk as "Armies" that we'll call companies. These companies should be available per region, and each available company should vary both in numbers and fighting ability and loyalty.

Company numbers:
- Companies in a region should be available to anyone with a full state in the region.
- There should be around 0 (new world) to 10 (Italy) merc companies available to use per region
- Only one can be used per region per player or ai.
- Companies are ranked cheapest to most expensive
- Companies hired by other countries still show on the list and show the country that's hired them and for the price they've hired them for.

Company fighting abilities:
- Companies should differ in fighting effectiveness, with cheap companies having more mercs but less professionalism, bad morale, and bad discipline.
- Top Tier companies should have very good discipline and professionalism and average morale.
- Companies have no loyalty other than gold so morale should be worse than countries armies
- Companies should be very expensive to hire and upkeep but should not suffer from reinforcement extra costs.

Company Loyalties:
- Companies should operate on a loyalty slider. Merc Companies want secure, steady payment.
- Hiring companies for long periods increases their loyalty to you.
- Not paying them their full upkeep decreases their loyalty to you even when not at war.
- Being in increasing debt reduces their loyalty.
- Companies with higher loyalty to a country will have more morale.
- Companies with high loyalty will be harder and more expensive to outbid.

Company Bidding and Payment:
- In the companies tab, where it lists the available and in-use companies, countries can offer bids to hire companies that are in use by other countries.
- However to prevent abuse of this feature, bids on other countries mercs are only allowed if:
  1. Target country is at war with you.
  2. You are in a different war.
  3. Target country is at peace, and you are either at war or at peace too.
This prevents at peace countries, attempting to steal valuable companies from players in wars that they're not involved with.

- The loyalty of a company influences bids greatly. The greater the relationship of a company and country the more expensive bids will have to be to lure them into breaking contract.
- Bids come with upfront costs, a deposit of a years payment.
- Upon a bid the merc company gives its current owner 6 months to offer a counter bid should they wish to keep them.
- If the country fails to bid higher after this time the company will switch ownership, exiled with black flag, and retreating to it's new owners territory.
- Newly hired Companies can not be bid on for 12 months.
- If the country counter bids a higher amount, you cannot enter another bid for that same company bid for 12 months.

Company Misc
- Essentially, the expense and unstable loyalty of companies mean a more realistic use of Mercs, with those benefiting most from hiring them being rich, trade nations, and used by other countries for short or life-threatening wars.
- It gives small nations such as Hamburg, Lubeck, Venice, Genoa, Florence and other Italy states, a realistic and fighting chance against the seasoned national armies of other countries, but of course, at a huge and damning price for the best companies.
- The Italian region, historically having the most mercenary companies and wars between them, should offer the most diverse, expensive and professional companies in the known world.
 
Merc's should be organised and brought in bulk as "Armies" that we'll call companies. These companies should be available per region, and each available company should vary both in numbers and fighting ability and loyalty.
<snippage>
Some nice ideas in this post, but I still like the idea of attaching mercenaries to trade nodes, in numbers related to the total trade value, rather than to regions. This allows a nice, organic means to dynamically set mercenary availability, rather than setting things up fixed to their historical prevalence. Outbidding/loyalty mechanisms and such are interesting; morale related to loyalty is very nice.