Re: somethings missing
The 'move_speed_mod' entry in the EDU is used in nearly all instances to slow down units - which means the speed is otherwise normal. Or are you talking about routing? The AI has a custom battle (and strat) boost, unfortunately it is via traits and requires a named character - but those armies should be reasonably difficult to beat, and the boost gets better on hard as well as very hard.
The culture across the region was fairly the same with the exception of the Northern Steppe tribes and the Southern Tribes (both having different units), so one should expect fairly the same units.
We have been tossing around the idea of unique units, but if one wants to stay within reasonable limits then there isn't really much to go with.