Caster Chocobo would get Choco-Meteor as an ultimate skill if they increase the rank cap, if only because Ultima itself is a plot-powered Doomsday Weapon.

Also, Choco-Meteor is the better option simply because people who've run afoul of All Red Chocobo random encounters in Final Fantasy Tactics will love having that kind of power at their fingertips. Or they might go into PTSD. Depends on how many times they ran into that particular encounter.