Husky65,
If the whole idea was just to get conversions fron Inf to Mot, etc., I might agree with this method, but my concept is for a wholly revised system that addresses several weaknesses with the current game while increasing the workload on the player to the minimum extent possible. I don't want a 'massive logistical simulator', either, if it means I as a player have to do the simulating! What I do want, though, is a plausible and realistically limiting logistical simulation with interesting decisions for me to make as a result. Let me try to summarise the whole thing for you.
Supply Centres
I introduce a new base type - 'supply centre' - that represents a mix of supply depot, railhead, equipment assembly plants and military training camp. It would be arguably 'more correct' to have these all as separate types of base but that would be complexity for its own sake, IMO, and unnecessary. Supply bases are similar to naval bases or air bases, but for land units. They have a size (1-10) and units may be thought of as 'based' at them, although Divisions will actually be automatically 'based at' the nearest one and draw supply from it, so this will be more-or-less transparent to the player.
Supply Centres actually do exist in the game now and hold resources, supplies and oil. The change here is that they are visible on the map and their placement is under the control of the player - because the placement of such bases is a key decision and may say a lot about an army's intentions.
Supply
Supply should come from Supply Centres as it does now. Land 'convoys', using TCs and vulnerable to attack by air or land (if adjacent to enemy land units and not protected), may be used to connect SCs. The 'length' of a supply route will count each province as 1 divided by modifiers for infrastructure and terrain. Provinces containing the source, the destination or both count at half value. The TCs allocated to the route divided by the route length gives the route capacity in both directions - sea convoys are revised to work in the same way. TCs are manufactured like sea convoys are now rather than deduced from ICs.
Supply from SCs to units relies on transport elements integral to the unit itself. ESE becomes the unit's supply element's capacity divided by the route length to the nearest allied SC; route length is a count of provinces divided by infrastructure and by movement and weather modifiers appropriate to the supply element type attached to the unit. All of this is, of course, automatic and visible to the player only as an ESE figure; it just means 'move too far from supply and you're stuffed', but how far is too far relies on several factors.
Trade
International trade must be set up as 'convoys' - either land or sea - from a source SC to a destination SC. This addresses the 'trade convoy freebie' issue and the 'can't trade with Nepal when at war because we have no sea connection - despite being right next door!' issue. The trade convoys are vulnerable to attack, as any other convoy, but part of the trade deal is "who supplies the shipping?" and attacking 'neutral' ships will have consequences...
Production
Units must be constructed somewhere - land units in a Supply Centre, naval units in a Naval Base and air units at an Air Base. This is nominated as the unit(s) is/are added to the production queue and is where they appear once complete. Factories are used from the area around the base the unit is made at and this affects the efficiency of the IC usage. Basically, making units at bases far from industry will be possible but slow and inefficient. This addresses the issue of a nation using all of its ICs to produce battleships at its one and only port, and similar oddities... A base can only produce as many units as its size at 100% rate - more reduces the rate proportionately - and bases may of course be bombed to reduce their effective 'size'.
Strategic Redeployment
Units may Strat.Redeploy only between bases; this takes up TCs or shipping convoys (as appropriate) according to the unit size and time according to the route length. Units in transit may be affected by attacks on the convoy route between the bases.
Unit Elements and Upgrades
Units are composed of three (or in a few cases more) elements. The base unit represents the trained manpower with personal kit and weapons only. The other elements are a 'heavy equipment' element and a 'transport and supply' element. These latter elements are 'attached' much as brigades are now. 'Heavy equipment' has a big effect on the unit's combat values; 'transport and supply' has an effect on ESE and may also increase unit speed, hardness and defensive values when combined with certain (light) 'heavy equipment' elements.
Rather than units 'magically' upgrading in the field, upgrades are done by swapping out old equipment elements for new. This must be done at a base and takes time dependant on the distance from which the upgrade elements must be drawn. Upgrade elements are created in bases just as units are - the route length between the base they are made in (or 'dropped' in, for 'second hand' elements) and the base the upgrading unit is in automatically determines the time to upgrade; TCs or convoys are used for this time, also.
The Mot/Mech/Inf issue comes in here as well, since these are essentially the same base units but with different HE and TS elements - elements that can be swapped in a supply centre. Cav might also be the same base unit type, but Mtn, Mar and Par would need specific training - though they could also receive Inf type HE and TS elements.
Potential 'additional' elements would be for air or sea landings (gliders and parachutes for the first, landing craft and other amphibious gear for the second). These would be 'one use', generally.
Certain circumstances - retreat to sea, surrender due to no retreat options - would separate the HE and TS elements from the base unit. Some of these elements - especially the TS elements, if real life considerations are to be modelled - could be captured and used by the victorious enemy.
Trading in military equipment would be handled by trading HE and TS elements - the base units would be loanable (expeditionary forces) but not directly tradable.
When units are added to the production queue, they would normally be added with the elements attached. Such usage would be just like the current system - a complete and fully functional unit pops out at the specified base when production is complete. The difference would be in upgrades and the possibility to re-equip for specific duties, if desired.
Optionally, TS elements could be attached to supply centres, boosting the TC available as long as they are assigned. General TC would be rail assets, so should not be convertible in the opposite direction!
Reinforcement
Reinforcement 'points' are required to reinforce units and these are distributed via the supply system just as supplies and oil are. Reinforcement should also take 'supplies' to represent the equipment losses, 'reinforcement points' being mostly MP. Reinforcement rate is affected by ESE.
So, you, see, there is a lot more to it than switching Inf to Mot or Mech - although that does get addressed more-or-less as a side effect. The only additional load on the player is (a) deciding where to put supply centres, (b) arranging upgrades (although you could just not bother and create new units with new gear) and (c) deciding up-front where to create units. This last you actually have to do now, but it is unreasonably limited and is done after the unit is already made, which seems a mite odd... Oh, and trade would be slightly more involved, since a 'from' and 'to' base would have to be specified as well as who provides the transport (although a default of the party offering the trade could be set). This last, incidentally, allows trade with USSR to be routed to Archangel (as was done in practice) when Lenningrad becomes too hazardous to use, and generally allows trade routes to be selected more freely.
This is obviously a system for HoI3, not a patch! But I think it does address several current issues and it has evolved to incorporate several comments and suggestions made here. More are, of course, welcome
