Here are a couple of probably already-know ones (and only changes made are shown):
-Siege Engines: Med-low offense, Very low defense, high bombard (range=0!), -1 or -2 H.P. (depending on how high average H.P. is in your game) and "collateral damage", with the AI flag as "offense".
Splitting up foot units:
-Archers: (which are more realistic IMO): equal off. and def., collateral damage, -1 H.P., AI flag of both Off. and Def., wheeled.
-Spearmen: Equal off. and def. (again), +1 H.P., maybe 5 sheilds more than an Archer of equal offense and defense, wheeled, flag both Off. and Def.
-Skirmishers: Fairly weak offense, 1-2 defense, -1 to -2 H.P., not wheeled, Zone of Control, defensive bombardment.
-Officers, and other high command: Quite high Off and Def, but still equal, req. Iron, high cost (or maybe even produced by an improvement), Amphibious, +2 H.P., wheeled, Zone of Control (doe to the moral damage it inflicts on the opponent), flagged both off. and def.
Is this the sort of stuff you are on about?