I'm not entirely sure about whether or not the Gunner class will actually heal. Neither Merlwyb nor the npc from the rogue quests looks like the type of personality I would want trying to "heal" me. I'm hopeful that there's another class which hasn't really been hinted at that can fill the healer role. It could also be that the Gunner may be similar to the SCH/SMN jobs where it has 2 job classes that fulfill two roles, and that Dark Knight is the only pure job class.