Im with Nekotee and Britton on this one. When i read your question my first three thoughts were dragoon, bard, and black mage. Black mage takes the longest to get there(you get their proc traits at 28 and 44), but i think its procs are the strongest(0 mana instant cast enhanced thunder 3/0 mana instant cast fire 3). And for the record, BLM still does good damage at those times when the procs arent cooperating with you and just dont want to happen. I dont personally play dragoon or bard, so i cant comment as much on those.