One thing that would be amazing, would be the ability to play multiplayer on the game map. Shouldnt be too hard to implement, or?
Other then that im hoping for more customazition, more sim-aspects, like more building choices for castles, more variety in troops, more ways to administrate ur kingdom and towns and so on. I actually dont think they need to do much on the combat system and the fighting, except AI pathing, formations and such.