Possibly, but I think it's hard to argue that even the Doviello and Clan are still ''barbarians'' when they have the knowledge of Currency, Iron Working, Arcane Lore, Writing etc etc etc.
Unlike the other civs, thematically the Doviello and Clan start the game as barbarians. This is represented with their peace with the barbarians which lasts until they have become ''too civilised''. However, I think their leaders are generally struggling to revolutionise their societies, leaving barbarism behind.
This struggle would be represented with a very, very slow start, possibly agrivated by banning them from building Elder Councils and Libraries, but if they can survive long enough to obtain civilisation their reward is the potential to become very powerful militaristically. After all, with the Clan's great numbers and the Doviello's warlike tradition, really all that is needed is to be advanced enough to make decent weapons for them to become a strong power.
I would probably link peace with the barbarians with a tech, at which point the barbarians declare war. I'd say Writing most likely. It is a pretty useless tech for the civs in itself, but it leads to vitally important techs like Currency.
That being said, this could probably damage the early rush element of the civs...
Well it's only an idea anyway.