Doesn't final fantasy dimesnions (mobile game) have a system with Light and Dark jobs? (Waiting for the Nvidea shield to get it cause I'm annoyed playing FF3 on my mobile)
also: Blue Mage in FF11, during the unlock quest I had the impression "Blue magic seems to be a forrbidden art and to use it you must sacrafice who you are to master the power"
(Plus necromancer is one of my favorite jobs in GW2 but that's not what this discussion is about correct?)

Maybe with these spells that drain your H/MP to restore another party membber's H/MP, why not make several "summons" have a minor inate skill that takes from the foe to give to you?