I would avoid any of the melee classes then, because for an optimal opener you have to weave in a ton of oGCD abilities, and continue weaving them the entire fight.

I.E. The Dragoon opener:

H -> [BL+BFB] -> ID -> [DRAC-POT] -> DI -> [IR + BOTD] -> CT -> [PS+ LEGS] -> 4TH -> [GK] -> P -> [JUMP] -> TT -> [DFD] -> VP -> [LIFES] -> FT -> [SPD] -> 4TH -> Repeat

Same for BRD and MCH. Summoner also has a decent amount of oGCDs to weave with the Aetherflow abilities.

So yeah, that pretty much leaves Black Mage.