No. For the last time. Don't add deaths to stats. People don't just pk... Would also take up too much space when you have 100,000+ deaths.
All they have to do is make people who die, spawn at random areas near the area where they died. Prevents mobs.
Pk zones? Isn't that what towers are for?
If you add a dedicated area for pking, then people will just boost there... it won't remove mobs. It'll just make it easier for them to gather around there.