^That duty finder thing is good news.
The part about a thief class though, I wouldn't get my hopes up. I read an interview a while ago (can't remember with who) that said the Rogue/Ninja class is as close as we're ever going to get to a thief class, because a Rogue is essentially a thief without the stealing and they aren't up for introducing a stealing mechanic.
That and adding another DPS class on top of the new DPS class would be dumb before introducing the new healer and tank.
If you think about it, with the new classes there are:
3 Melee DPS - Monk, Dragoon, Ninja
3 Ranged DPS - Bard, Summoner, Black Mage
3 Healers - Scholar, White Mage, New One
3 Tanks - Warrior, Paladin, Dark Knight
So after the expansion pack things are finally balanced.