Just a random idea (and not likely popular) the Blue Mage could have made an excellent Healer. It has lots of heals and shields and buffs and a few damaging abilities (if we ignore the boss abilities weirdness). In particular i think the suicidal sacrifice heals could be very interesting and clutch in dungeon boss fights. Much like they do with all the other classes they could have simply had each ability learned locked behind a monster fought or hunted down for their job quests. (And removed the boss abilities skills completely)