Or Blue Mage can just stay as Blue Mage. Odds are we'll "learn" skills via the Job quests and depending on how far SE go with it, learn from bosses in dungeons and raids.

Of the coloured Mages, Black and Red have stuff to do with the Void. White Mages do not. Let's balance it out and have Blue Mage having nothing to do with Voidsent/demons.