Considering fallout tech had removable limbs I don't see why they would dumb it down for Skyrim and remove a great feature that added value. I doubt there will be any sort of fancy system, but rather once you get skilled up there will be an increasing chance of head/limb removal on a blow which would kill the victim. I mean what wouldn't be more satisfying than a built in "deadly reflex" of sorts? Time will tell, but if they said it... I think they meant it literally because it is too descriptive.
Bethesda as mentioned before that they liked the deadly reflex mod/mods,same as the bedroll mod and archery mod. And we know what happened with the archery mod they liked.
They put it in skyrim as default