The question which requires more thought is... what happens when a nation mobilizes, and suddenly you annex/inherit all their units. And it's a whole bunch of them. Say for example, playing as Prussia, you unify Germany in the wars against Austria & France... and you suddenly get a whole bunch of units (like, a 1/2+ million man army) from all the ex-German minors.
What do you do with that plethora of troops, who are... a bit less reliable... a bit less firepower/defense/shock/morale/ORG, etc. In fact many of them are not even of 'regular' quality. Yet... they are not technically from your mobilization pool. You never mobilized. These units are now part of the 'standing army', as of the moment you inherited them. You could keep them, but, they are a very inefficent use of your own manpower. Plus they take higher casualties, so not only are they going to require a lot of soldier POPs to support them, and occupy a lot of manpower points, they're also going to deplete your soldier POPs at a higher rate since they are 'lackluster' in combat... compared to the 'real' troops.
My solution was to group the majority of them into 2 large (about 200k men each) corps, the I. and II. 'Reserve Armeekorps', and give them a leader that A) significantly improves reliability, and/or B) significantly reduces attrition. And always be careful to avoid a stacking penalty, when other corps are nearby. Just always have the province secured, by the 1st of the month, when conducting envelopment maneuvers. 26% attrition is obviously not acceptable, under any circumstances.
But yeah, use their sheer numbers to take/occupy ground very quickly. Plus, the AI is scared $hitless of troop formations of that size... and rightly so. Working in tandem with your 'elite' units, I've found that you can wipe out an enemy force of 40,000 troops, at level 60 entrenchment, at a place where the topology is tough... and totally quickly slaughter them down to the last man, only losing a very few number of your own troops -- hardly any, really. I.e., the sheer numbers alone, can be very helpful -- in (very quickly) depleting an enemy force that would otherwise be a tough nut to crack. Sort of like with the Naval warfare... a giant stack has great advantages. And needless to say, they can take a province in a handful of days... greatly assisting in the 'blitz' effort... keeping the enemy off balance, on the run, out of entrenchments, out of morale.
But that's my debate right now... how long should I keep them. I'm thinking when the next wave of army techs (the level 4 crap) becomes available here soon, and I finish it... I'll revamp the whole army, and get rid of (replace maybe) those obsolete units. But, these guys are mostly vanilla infantry units, so they're real cheap... and having that many men around has it's advantages.
Anyway, the ones that don't get thrown into the 2 'Reserve Armeekorps' wind up in slightly diminished capacities... like 1/2 strength maybe, and I put them in various places where they can keep the people under control, in the newly conquered lands. Once they entrench to 60, they can easily do the job, especially in rough terrain/topology. Some rebels pop up, and fight at 1 to 25% efficiency... so the low strength and lesser stats don't really matter.
So, maybe there IS a place in the Grand Armee, for a rag-tag group of amateur scoundrels... vanilla infantry can have it's cost-effective advantages, when you have an enourmous, overwhleming pile of them (with a great leader).
But as always... mobilizing, and forcing a bunch of clerks and craftsmen (along with a bunch of laborers from the 5.0 precious metal mine, etc.) to go die in the field of combat, en masse... nah, that's just never classy. Most decidedly not a 'good show', as they say. You want to convert a bunch of guys from the 1.1 fruit producing province (which was hit by insects)... put them into uniform, and send them to die -- gloriously.
And of course, when you conquer Danmark, you convert a bunch of them to soldiers, and then put the 'Danmark Armeekorps' right into harm's way, all the time. Of course those units all have regulars brigades... just to add to the thickness of the bullet sponge. Then when you annex southern Sweden, you do the same thing there. Those places where the RGO is weak... take those farm boys and create a Schweden Armeekorps. All these units will have leaders that improve reliability, naturally. Next thing you know, you're just like Alexander, or Napoleon... and you've got a bunch of conquered people fighting & dying for you... so you can keep conquering the next ones...
