DoM is pretty useless, I agree. Every job can heal itself. Every job can buff itself. Every job can even use our mage armor to cast spells if they want. Why do mages get invited? So that melee jobs can mindlessly spam "1" and not really have to watch their HP or worry about buff timers. It isn't just the fact that Mages, by themselves, are useless in this game. I also blame the current armory system...any job can use (almost) any skill and any armor from any class at any level in any area at any point they want.

Oh and the guy on Figaro that solod Dodore as a THM, cheated to do so. Keep that in mind when you start thinking "How are they useless if you can solo NMs!."