In theory, you could kill someone but pooping a vien in their brain or something else of the sort. It would be much more practical and efficient opposed to creating fire, and launching it, and doing it over and over until the pour soul dies. Of course the amount of nerdrage caused by would be insane, so they go with the typical "make this water and powder magically heal this douche" approach. Anything else would require complete re-innovation of the magic system and reinventing the way magic systems are done in a game, all while keeping it balanced. So don't get your hopes up.