Sorry, but I have to disagree with you on this one. It sounds like an RTS gimmick. This game is no RTS.Here is another idea I've been toying with. Not sure if it's even possible, but I'll throw it out there maybe for the next game.
As we all know, in real life there are way more variables than in any game. For example, leaders like Napoleon and Jackson could get their troops to marcher faster and longer than other generals, while McClellan was great at organizing, Lee great at defense, etc. I think it would be great to have the player choose their "style" before a battle, which would then give a bonus to a certain aspect of their game. The player could choose from predetermined historical styles like Lee or Jackson, or pick something like two attributes to create a custom player style.
This way, the player could custom tailer their armies to strategy. Want to dig in? Go with Lee. Want to have better artillery? Go with Napoleon. Want to have faster marching speed? Go with Jackson. Want troops that are less affected by units retreating around them? Go with Grant. And etc etc.
This also brings me to another point that was present in the Waterloo and Austerlitz games from the SMG engine: unit cohesion. As units marched, fought, retreated, etc their cohesion would suffer just like morale. I think this would be great if it was implemented in the game just like it was in those two titles. And with this, choosing a McClellan style of command would give your troops a boost to overall cohesion.
Thoughts?
Fatigue is taken into account and I believe that it affects morale and general combat effectiveness. Not to mention that units with a higher fatigue cannot follow through with more arduous move commands such as run or charge.