I like the idea of the FFT:A system with advance classes and I think it satisfies the original intention for people to lvl a lot of jobs to become more useful or "well versed".

The not advanced classes will need something though to make people want to lvl them outside the norm...maybe not for high lvl content but for some sort of skill, trait, etc that makes it worthwhile to have a lvl 50 Thaum instead of a black mage.