The thing about Rogues and twf... they don't really care about vase weapon damage. The best weapons to use is actually the dagger as they can TWF and throw or stab with the dagger.
Even if you let me sneak attack with a great sword, I'll stick with Daggers for the most part.
Barbarians get slightly shafted, however you could allow the martial Adept feat to grant a fighting style ? Or something like that.