Kinda two parts here.
I'd really like to see jobs each get their own individual animations for their limit breaks, even if they do the exact same thing. Being a monk, and suddenly pulling out an energy sword just don't do it for me. Would be nice if they did something specific for Monk and Lancer. Maybe even with subtle differences... like the Monk LB causes paralyze (since blunt damage seemed like something that would hinder your abilities. Perhaps Lancer can cause a bleed effect after use. But more importantly, they use their fists/polearms to do these moves.
I'm reminded of Saga Frontier, and the unique combo animations they had. I'd like that. (except not ps1 quality).
For Healers, perhaps White Mages bow down to the gods in their healing animation or draw enegeries from teh earth, Scholars perhaps have some fancy book animation or better yet, their Fairy could do some fancy ritual.
Bards, assuming they don't have a ranger counterpart, should really have some form of DPS LB.... or at very least, one that buffs the party. Maybe like an Embrava affect, like from FFXI Scholars. A Powerful TP Song, Regen Song, Refresh Song simultanouesly, and even better, make it only use one bar regardless instead of 3.
As for Tanks... Would be interesting if they did the same thing but in different ways... maybe the Warrior limit break would do an equivalent ammount of HP as Paladin's would defense, with Paladin animations playing off a virtuous knight and Warrior's relating to fury/rage etc.
As for BLM/SMN I'd mostly like to see Summoner do a animation based off their Egi doing the limit break, instead of a meteor. I know it'd be a pain making a different limit break for Carbuncle, Ifrit, etc. But it's kinda Tradition for it to be a flashy job involving getting overpowered beings to do big things on a player's behalf.
Maybe I'm asking for to much :P.