Ugh...that's a toughie. Melee DPS is definitely out considering how scripted their rotations are and with SMN and BLM gone as well, there's only MCH and BRD left as possible candidates.

Now, I can't speak for BRD (yet), but MCH has a very scripted burst phase, so that might be a turn-off. Otherwise, you can watch the mana/tp bars of your party and react to your shot proccs/ammo CDs.

Uhm...yeah.