My only concern about the revelation that the map is going to be 30% larger is that, IIRC, In Medieval 2 the zone of control is still small for an army. A larger zone of control is, to my mind, the only worthwhile contribution from Empire to the future of the Total War games. Will you be able to hold strategic passes, I wonder? Or will there always be room for an army to sneak past?

I am not a coder in the least, but it would seem reasonable if after an army was stationed at a place for a while, its zone of control expanded, reflecting scouts and established control and lay of the land. I doubt though that the zone of control can be altered by programming.