Perhaps an additional distinguisher for Barbarians would be (and this is WAY out there, I know) a big difference in their training. They would start with no home town, somewhere in the forest. They would have to find food in order to survive. They would not train very effectively in the classical way, but rather learn their skills "organically," starting out with more of them and advancing a bit faster than others with experience.
In other words, a barbarian could learn Elvish from a trainer, but it might take twice as much time and coin as for anyone else of their intellect. On the other hand, they would learn faster from experience, and would start with a broad range of ranger-like skills.
They would also have the classic barbarian stuff, like rage and fast movement.
Clearly, this would require that they be chosen at character creation, rather than be an opt-in guild for fighters later in life.
Barbarians
I -really- liked Raona's idea. But I was thinking that instead of having "no hometown" or "guild" a barbarian's guild/hometown could be made. I had a lot of ideas for a guild/town for barbarians when builders were first assigned to the task, but I was just a designer whose builder sort've left. If I still have them, I could e-mail them in or tell someone about them or.. something.
Jamais arriere.