1. Lack of on NPCs
This has the potential for metagaming as a loitering shroud can be examined to tell if it's an NPC or PC. I'm sure it's easy to catch if someone is exploiting this, but it'd be nice for people to not have the opportunity to. Also it'd just be nice to be able to cut things off of NPCs in general.
2. Expanding what you can
I don't mean fingers and toes, but expanding it to include, for example heads (yes that would kill the target) would make for wonderful opportunities to throw an enemy's head into a bar their colleagues frequent (which is currently impossible) and so on.
3. Including corpses as targets
Just because someone is dead, doesn't necessarily mean you don't want a trophy/proof of having killed them.
4. Longer body part shelf life
I realize that having body parts decompose to reduce/prevent bloat makes a lot of sense, but currently a severed leg decomposes about as quickly as a gouged out eyeball. I'm not saying a severed body part should decompose at the same rate as a corpse and go through the stages of decomposition, but it would be nice if they lasted a little bit longer.