A little food for thought.
In Warhammer Online, there is a Class pairing - the Dwarf Slayer and the Orc Choppa. They are basically a whirlwind of steel, a high DPS melee class that can put out good area-effect damage but if they let their rage go unchecked, can take more damage. They can dual wield or use two-handed weapons. They are very similiar as mirror classes tend to be in WAR, with some slight differences.
Perhaps the biggest difference though, is that there are significantly more Choppas than Slayers. Why? Because Dwarfs, in the history of MMOGs, are always an unpopular race to play as a whole.
I don't really have the wherewithal right now to say how this should play into designing something, but I'm sure it's relevant.
