I hope they never increase the job level. While I think it would help mages of all stripes by giving them access to Convert, it means old content becomes irrelevant. one of the best parts about FFXI is that the gear from Tu'lia, a raid zone that's been in the game for 5 years, are atill viable and in fact are in some cases still best-in-slot. Every time WoW bumps the level cap, an entire expansion's worth of content becomes irrelevant. Fuck a lot of that, I say.
PS: Jobs that fail? BLU, COR, DNC, and SCH are all amazing and PUP, while not that great for group stuff, is an extremely strong soloer and is treated as such. The only classes in the game I would honestly say are not very good are DRK (which at the very least has Kraken Club retardation) and THF (which is still sought after for endgame solely on the basis of Treasure Hunter).
EDIT: WHM has problems at 75, but that's another story.