Uhm, necro as a party-support-healer class seems very odd to me.
I don't think anyone but a madman would deal with necromancy, to heal people; you might as well just become a CNJ and heal people; But i suppose it's a regional thing, since Ul'dah/Limsa don't really have CNJ.
I'm pretty sure most people would find it repulsive for someone to dig up a corpse, blow it up, and heal you with necrotic energy. Would feel like having diseased corpse worms crawling around inside you, repairing your tissue with their saliva; you wouldn't be much of a welcome addition in any party...