This sounds like a mixture of some current MMORPGs out there and a rip from the Final Fantasy Tactics series. I really like this idea! In fact, I had written on a piece of paper while I was at work, some Job Classes that were to be unlockable, even new introduction classes such as:

Performer: >>Dancer<< >>Bard<<
Mathematician: >>Scholar<< >>Blue Mage<<
Musketeer: >>Flintlock(Rifle)<< >>Cannoneer<<
Conjurer: >>Black Mage<< >>White Mage<<
Thaumaturge: >>Red Mage<< >>Geomancer<<
Arcanist: >>Summoner<< >>Elementalist<< >>Illusionist<<
Gladiator: >>Paladin<< >>Fencer<< >>Samurai<<
Marauder: >>Viking<< >>Dark Knight<<
Lancer: >>Dragoon<< >>Templar<< >>Chocobo Knight o_o<<
Pugilist: >>Monk<< >>Ninja<< >>Thief<<
Archer: >>Ranger(GreatBow)<< >>Sniper(Crossbow)<<