As far as i know there hasnt been any significant unit additions or changes after the kingdoms units addon and the units are very much vanilla. And i like the vanilla unit feeling in the game. However if you are about to add custom units in to the game which you probably do, i would suggest that make those units as much as possible to be "vanilla" fitting, for example if we are about to add Kontaratoi Pikemen to the Byzantines, it could be possible just to make a byzantine vanilla texture unit with pikes and so on to keep on the feeling and improve the unit variety in the same time. I think it is either or situation: if add customized texture units then rework all factions, and if not make the added units vanilla like. However, this is purely just a suggestion of an idea or something like that