These are just some suggestions to increase PVP and player interaction on the server, some are my ideas others are blatantly stolen:
1) A Monthly or Weekly prize (z-coins or premium gear) to the player with the most “legal” player kills
2) “The Thunderdome” – 1 on 1 arena combat with limited equipment. Single elimination bracket. You would enter the arena with no equipment or armor(or possibly basic leather) and use what you find inside.
3) “Battle Royale” – same as above but no number limit – last man standing.
4) “Capture the Flag” – I’m sure you can figure it out.
2, 3, and 4 would require a special location and would be scheduled events. I would suggest the arena be built just north of the Hub City in the PVE Zone, just to keep the spectators from killing each other.