Geomancer would be awesome, but they've harnessed alot of weather related elements into summoner n stuff so in my eyes it's unlikely. Time Mage seems to be the most logical, if it doesn't come now it probably never will... But, I don't see how Time Mage would work in FFXI.

Chemist, now that would be good! Also, the job I've always wanted to see in the game is Mime.