Because I'm a mage and not a warrior, I'm wearing mage-robes and a dragon-priest mask.. and some other stuff. Then I encounter a draugr death lord, who, with one arrow, kills me. Or in fact, almost any contact with him will kill me instantly. So I decide I'll use a Mater destruction spell.. 5mins later, still casting it and oh, he shot me, I'm dead again. It's basically whoever hits who first.. and right now, mages take way too long to attack. And even with those massive master destruction spells, I never have large groups of enemies to use them on.. so it's kinda pointless.