I definitely support Drakontos' proposal of Roman, civilized/ Romanized Barbarian/ Barbarian, which could be divided into Germanic, Steppe, and Barbarian.
Cultures rundown:
Roman - WRE, ERE
Romanized Barbarian - Visigoths, Ostrogoths, Franks and Romano-Britons
Germanic - Saxons, Norse, Burgundians and Alemanni
Steppe - Huns, Vandals(?), Alans, Gepidae and Venedae.
Barbarian - Illyrians, Berbers.
Eastern - Sassanids, Caliphate. Copts?
My biggest question while making this list was, do we have a
culture slot limit?
So we have racial traits? Sounds ok, if a little complex. If modders are ok with it, I don't need to worry about that.Even this could be further broken down into individual tribes within confederations - but I think distinguishing between the ex-Roman majority of the population (more apt at administration) and their Germanic rulers (better equipped for war) would be quite fun.
How do you do that? I can only imagine the Alemannic tribes having tribal traits. The ex-Roman population wouldn't be generals anyway, unless married-in or serving Germanic generals as personal retinue. We can indeed reflect their "more civilized ways" through these guys, if that's what you meant.