Except that tanks can do support, DPS, etc., and most DPS have some amount of utility, so what should those be renamed. The names of the roles are their primary jobs. Tanks, even though they can give defensive buffs and even heal sometimes, their main job is tanking. That's what they have to do. DPS, although they can provide some buffs to the party, their main job is attacking. They're the best at it, and it's what they're supposed to do. Healers... well, I'm sure you can guess.