
'Thief' has been stated by Yoshida as being part of the longer term considerations, but I believe the suggestion was it would be a Discipline, with Assassin and such like being possible jobs from it and.. yeah, very speculative. Among other things I particularly remember something like 'we do want to add dual-wielding, but we don't know if we want it to be a Gladiator ability or something for a future Thief class'.
As for the job system.. well, it's pretty simple, but I'll not link since the details are - until the lodestone update they'll probably drop next week - rather scattered about. 'Long and short of it is it's a specialisation system. You get to a particular level (25-35-ish depending, I think) in the required Disciplines, then do a quest and get given a stone that you equip to activate that job, like how you activate a Discipline by wielding one of its weapons.
Jobs don't have levels independent of their associated Discipline, but rather you do quests to unlock their special gear and abilities. They're much more powerful in their specific roles, but have little to no cross-classing ability as do Disciplines. The whole concept is pretty expandable, and the developers have suggested a few times there'll be more Jobs down the line as well as more Disciplines, more than one for each Discipline at that. Gladiator > 'Dark Knight' for instance seems pretty likely from the things have been said about it.
As for the job system.. well, it's pretty simple, but I'll not link since the details are - until the lodestone update they'll probably drop next week - rather scattered about. 'Long and short of it is it's a specialisation system. You get to a particular level (25-35-ish depending, I think) in the required Disciplines, then do a quest and get given a stone that you equip to activate that job, like how you activate a Discipline by wielding one of its weapons.
Jobs don't have levels independent of their associated Discipline, but rather you do quests to unlock their special gear and abilities. They're much more powerful in their specific roles, but have little to no cross-classing ability as do Disciplines. The whole concept is pretty expandable, and the developers have suggested a few times there'll be more Jobs down the line as well as more Disciplines, more than one for each Discipline at that. Gladiator > 'Dark Knight' for instance seems pretty likely from the things have been said about it.