I am not wading into the Roman discussion but I just want to point one outcome of what you are saying would be the class Barbarian isn't tenable. Again, I wouldn't point so much to history, because this is all pretty removed from a 2000 year old conflict between Rome and Germanic tribes. But I think it's a powerful image that people gravitate towards and want to play (I love Barbarians as a class and love Conan the Barbarian as a character). I wouldn't look to Conan for an understanding of humans in our past that were labeled barbarians, but for a fun sword and sorcery world where we are guided more by imagination than logic, I think it works really well