I've said this in several threads before, so apologies if you've seen this:

The patch around the Heroes' Gauntlet also included several quests in the Crystalarium.

In there, the bosses added were specifically "Berserker", "Thief" and "Necromancer". The quests in town included a girl who wanted to become a sort of combat "Chemist/Churgeon" (Sorry, I forget which was specifically named).

I'm of the belief these were specifically to say these will not be added in as player jobs despite players constantly wanting them. As in, Yoshi-P can joke "Players requested we add Thief to the game, so we did!"