Oh there are so many regions which deserve some uniqueness. In all fairness: does one really believe Pantodapoi from Syria look the same as Pantodapoi from Baktria?

Or would the 'Eastern Axemen' from Mazaka be a virtual copy of those found in Anticoheia Margiane?

My guess is that they wouldn't; but if you want to model such differences which is for all intents and purposes 'more of the same, with a different look' ... then the unit limit is not just a limit: it's the end of your dream.