The only problem with that is that a lot of those jobs have weapons that don't go with a class. The way it seems like it's gonna work, is that equipping a "job stone" to a class will turn it into that job, presumably using the same gear it could before.
They could just make it so that there are certain weapon types that are only equippable alongside a particular job stone, but I haven't heard anything from the devs implying that to be planned or even possible. I guess anything is possible when it comes to 2.0, though.