White mage. If specializing in jobs gave us new spells and skills they can also take some away. Eg. Playing as Whm/Conj would make your healing spells more potent, longer lasting buffs, more buffing spells like haste etc. In exchange you would lose attack oriented spells like fire, aero, earth, drown, etc.

This might work vice versa but I'd prefer healing when playing a mage