What would be really nice is if Cure spells didn't do half damage to undead, considering that the things can already resist on top of that. Being able to only do significant damage to one type of mob wouldn't be too bad for other magic damage jobs, and it isn't like Black Mage is the only heavy magic damage job anymore anyways. Additionally, more Banish nukes wouldn't hurt, as they would probably be fairly weak anyways. Currently I mainly use Banish/Holy for skillups and managing mobs while PLing people, and the occasional killshot snipe (the first time I ever fought Promanthia, we would have wiped at 1% if it wasn't for a well timed Holy).

Of course, White Mage getting more damage potential is mostly important if other jobs continue to get more healing potential, since adding more healing to White Mage to compensate may be difficult.

More importantly then even getting better nukes, I'd like to see Reposega. Repose is almost never resisted for me thanks to its high accuracy and my near-cap Divine Magic, even without magic accuracy gear. Seeing an AOE version of this would be nice, especially since Bard, the traditional light based sleep job, is getting a better AOE sleep, meaning we wouldn't be stepping on anyone's toes. Personally, I'd mainly use it for bypassing shadows, and sleeping groups of undead, since there are usually more capable sleepers in my party. Additionally, I think Paladin deserves Repose, since Dark Knight gets Sleep, Sleep 2 and Break.