I think it would be a great feature, and a lot of fun for the individual player, if at the end of each Grand Company, when you attain general rank, that you're able to undertake class quests with the Grand Company leaders, and learn their individual classes, or jobs.

Raubahn could teach Berserker, a dual wielding sword DPS class.
Merlwyb could teach Dualist, a dual wielding gunner DPS class.
Kan-E-Senna could teach Geomancer, a magical Tank class.


I haven't really thought about specifics at all, I just really think this would be a great addition, and a huge drive to complete each GC.