Every character has a caster-y enigma skill now, so you don't have to worry about catching a wizard or any of that nonsense. I guess, it's just my thought that you should use everything given to you and try not to limit yourself to just one "type" of duel. (example melee vs melee)
I'm hoping that they add a few robust options for creating games so you can tweak pvp settings, like you're talking about, but it might be an expansion thing at this rate.
Also, they've said that going 3v3 will help stop the rock/paper/scissors fights that pop up in 1v1.