For historical authenticity should be choosed the correct anthropological types of units of different factions. For example units of Andronovo Culture (http://i.imgur.com/OfETmhe.jpg) choosed not correctly. They should be not brunettes, but blondes and browns, as the Scythians, Germans, Celts in Vanilla. By type of face they should be similar to Northern Europeans, such as the Germans and not the Front Asians such as Armenians.
Andronovo Culture types:
Hair color of Andronovo Cultute woman: