well, on second thought about this. NPCs can now detect items on the ground, and most certainly other things they need to detect while cutting wood or such things. so tell me. if they can detect weapons lying on the ground, how could they possibly NOT detect bodies?, if it was in some demo of skyrim then you know how many months of development remain. plenty of time to fix it.
However. i just got a nice idea for stealth characters, traps!!
since you can now make traps with spells, you can go into sneaking mode, put a weapon on the floor somewhere around an npc's path, pick up a bow and draw it, and once the npc bends down to pick up the sword you shout "Boom Headshot!"