Also consider the fact that axes have very low dex req.
Of course this argument is useless if you're using a shield.
An argument for swords would be that a not-so-rich barb has an easier time finding a weapon, since stuff like grandfather and doombringer is much cheaper than runewords or death cleaver.
Although Zerker is a better choice in many areas. When I need a fast, indestructable weapon, pb is the choice.
While I certainly don't want to master 2 weapon types, and there're swords that're almost equally as good as axes, I'll stick on swords.