Considering the other specializations are Necromancer or Force Mage, I'm guessing healing is a standard skill tree now. He could be a KE given his sword in the concept art. But, going by the survey, he's out to remove the corruption from Tevinter, Necromancer/Blood Mage is out. I dunno, we'll see.
Ideally, I'd rather companions have their own specializations as they were in DA2, it helped define the character a little more.
Perhaps he is a battle mage who focuses on aiding and sustaining his allies health and endurance in combat, conjuring healing auras, magical shields that absorb enemy damage, and enchanted weapons.
Yes, I like that. Lets go with that.