i had a thought yesterday that would be epic if they implemented it, a little feature called "Organization". Every army would have a certain level, the maximum and minumum depending on the culture and the general leading the army. The fluctuation between maximum and minimum depending on certain traits, how long the army has been on the march, perhaps even how long the soldiers have been together (so merging two depleted armies would lower organization), if a battle has been fought recently (and if it has been won or lost).

Organization would effect morale mainly but perhaps also what battle deployments would be available :D