From Leaders portraits to causulty listings, what do you want to be added to the new Victoria 2?
Keep it simple (stupid).
No tactical battles. This suggestion pops up every now and then, the problem is that there'd be thousands of them.
Anyway, a better mobilization as mentioned. No million-man armies being nowhere one day, and there the next. May I remind you that at the start of WW1, the projected mobilization timeframes where of extreme importance to military planners and the initial movements at the start of the war.
In the game this should would work in the way that mobilized divisions do not become available all at once, rather it would depend on how compact, advanced and the infrastructure of the nation and the home-province (or state) of said division. Also, when they are first put up, they would have lower strength and org, and would be unable to move until strength is full. Maybe they'd have a flag saying "getting mobilized", this would simulate remaining soldiers and supplies arriving. Technology, infra and peacetime investment could lower or practically remove this effect.
In battles I think the EU-like marching to battle system is better compared to "movement is attack". Maybe a hybrid system where if enough troops face each other you enter the movement is attack phase? Or after some tech? Whatever isn't too costly on the processor, but remember that you have several years of experience and many good systems tried out. Use them.
About statistics, I think having lots of them would be good, but there should be an option to wipe them from the save, lest we end up with 20mb+ save-files that end up slowing down the game.
And no rebel popping. What is it that makes it possible for 10.000 men to get weapons and training to be able to fight, just like that? A better system is needed, rebel popping is not very realistic and not very fun.
An easier way would be to make peacetime mobilisation so ruinously expensive that once you mobilise you almost have to use your new army. So if Germany and Austria both mobilise then either one of them backs down (thus inviting an invasion from the other power) or attacks before they go bankruptHaving said that, there could also be some kind of system (a variation of the BadBoy, if you will) which would represent tension between states. Once that tension is too high, and if either state initiates mobilization, war is automatically declared between the two
Consumtion of canned food, ammunition & small arms/guns for fighting divisions.
If you can't supply them with whats needed (via a HOI3 like logistics) They fight much worse