When I read the letter from the producer where Yoshida hinted at the new job system I started wondering what it'd be. Before that announcement I thought we'd be getting a simple advancement or specialization jobs for our current armory system; however the way he announced the job system made me think otherwise.
Yoshida mentions the job system seperate from the armory system so here is the theory I came up with to make sense of it. They're simply going to add a job system in place of physical levels. Our jobs will be how they implement the traditional classes (it is a job system and traditional Final Fantasy classes are almost always as far as I know called jobs). This way they can get rid of physical levels yet still keep a little bit of complexity to the leveling system. In FFXI you could level up a job and then the weapon and magic skills within that job. In this system it seems we'll have a kind of job system (that'll get job abilities, traits, and maybe the two hours they mentioned they are working on) and the armory system to replace weapon and magic skills. Every job will be capable of using any armory class to a varying degree of profession. Maybe a white mage learns cure spells from armory classes at lower ranks or uses less mp or something.
It's just a theory I came up with while waiting, tell me what theories you people have and if you like mine~