Fog of war would maybe be cool, so you dont really know where the enemy is…it would add an element of caution and surprise! And realism… Or as an option for custoum! The old C&C games and Warcraft had it as an option! There was this old game “sudden strike” where a higher ranking officer saw further in the fog of war! A mounted ubit for example could get that advantage due to the natural elevation of the horseback!
And also night battles maybe…with fire-signal arrows! I am not sure how night would be emulated in the game, with darknes limiting the vision, one way would be with glowing aim circles for ones own troops and the enemy would naturally remain in some kind of darkness! As it is not unusual to forget a troop here and there in the midst of micro, I believe that element would even make that a lot more of a factor!