So this is a thing that I have wanted to see in many games for a long time, and I am wondering if CA will have it. I have suggested it to CA before, but so far it has not been used in any of their games. For this one though it is much more important.

What I mean is a system by which certain important unit stats and traits could be manipulated through a system of training, retraining, and combat experience. You can (for a certain amount of gold, at the cost of training other troops, and in a certain amount of time) re/train your troops in certain areas if you have the right tech, facilities, and officers. Things like military marching drills that would improve rank cohesion and formation changing speed as well as marching speed. (of course all these things would have and upward limit and be hard to improve as they get higher) Firing drills could decrease the chance of a gun exploding, a misfire, and decrease reload time. They could even be trained in and have their skill improve in certain maneuvers, etc.
Combat experience could effect every important things like morale, movement speed and fatigue level, reload speed. Likewise if a unit does not have combat experience for too long, these things could start to disintegrate.

I have said this many times before, I hope that CA has tried to implement this somewhat this time around. The different levels of discipline among armies as well as what they were trained with and what drills they had played a huge part in their success or lack there of. Also, combat experience counted for a lot in making a good soldier.