Monsters have minimal impact on fps and I can guarantee you that removing few mobs while having 100 players around that are taking actively taking part in PK wouldn't make slightest difference in fps.If mobs annoy you there's Etherblade or Plume area where they are non-aggressive...
Removing mobs has been discussed and denied already.
did you actually read the answers to this?
So mobs in Silver Pool, West City Outskirts, Plains of Farewells and Desert Bandits in Land of Buried Bones. That's all I guess.
^^^^^^Agatio already answered lol...