Personally I'm hoping that theres are no requirements from the Armoury System to engage in and enjoy the Job System.

IE

No matter what your Weapon Rank is, you can set a Job Title to give you bonuses to playing a certain role/jobstyle. Then you equip your weapon to determine how you perform that specific Job. All without limitations.

Yes, that means I'd be able to play as a White Mage / Marauder but to be honest, Doing so sounds Awesome.