The High Concept should include the class your character thinks he is playing.
Based on that you can choose the magic powers.
I think a character like that would probably best fit something like Mage, Priest, Paladin, Druid, Shaman, maybe a few others.
Mage is pretty straight forward: either pick a template like Sorcerer or Wizard (Sorcerer probably fits better), and let him have some of the standard spells like fireball or frostbolt.
Or (taking WoW as a baseline): let him be a focused practitioner with either arcane (spirit), fire or frost specialisation.
Priest would be a True Believer, although that might not be right, because he does not actually believe. Again a focused practitioner would be the way to go. Put the focus on something holy and you should be good to go. Remember, that you can not just throw out healing spells like you can in an mmorpg. You can (and should) however do a great deal with blocks and helpful maneuvers.
Paladin is pretty much the Fist of God type. Again, that template requires true faith, so again, a focused practitioner would be best. Maybe only ritual(holy) and some refinement, so you can enchant a weapon and maybe bless you and your friends with a "prayer" before you do battle.
Druid is easy, either a wizard/sorcerer with druidlike spells, or a true shapeshifter. Might be tough to get enough beast powers to be efficient in every single one of them, but you can still do a lot with it.
Shaman is simply a wizard/sorcerer with a focus on totems and ancestral spirits. You can do pretty much anything, as long as you keep it "shamanesque". Possibly a great focus on thaumaturgy rather than evocation.
All in all, the character pretty much builds itself, ones you have chosen a class that you want to derive your power from. You might also think about having him be an emissary of that exact class, having some sort of "god" somewhere in the nevernever, that has been created by so many geeks "believing" in this class. Think phobophages in PG, some of them had taken a form of general believe as well. The character would take his powers directly from that "god", so it would be sponsored magic.
I think as a GM I would compel the trouble aspect almost everytime the player is hesitating to go into battle, because if he dies, he would simply "respawn", no harm done, so why be afraid to die?
