How many times has it happened to you that you kill a player while there are other players in the area and it was simply too risky to go loot him?
Considering that in 4.0, when players die items won’t drop all around them, but stay on their corpse, I think it would be a good idea to be able to drag corpses (or any other ragdolls) around.
This would allow you to retrieve the corpse of a fallen foe (or comrade) and drag them away to a safe spot to loot them later, instead of having to do it in the heat of the battle.
Dragging corpses should slow down the player significantly, but allow the player to maintain a low profile, and carrying a corpse on your shoulders would make you more noticeable, but would slow down you less and allow you to use weapons (with accuracy reduction).
What about being able to hide behind a corpse e.g. when you’re being shot at? (idea borrowed from SAO Alternative: GGO)
Also, imagine making a pile of zombie corpses.
Having to completely pulp/butcher a zombie corpse to prevent them from getting back up would be cool. Low spawn rates, but not pulping/butchering would mean they get back up and come after you again. Exploding zombies wouldn’t leave a corpse though. (borrowed this idea from Cataclysm: Dark Days Ahead, sorry)