There is no world pvp in this entire game.
Except on the RP servers, where we seem to have motivated and creative players that actually bother to go out and make their own events and flag themselves for PvP
rather than asking for everything to be handed to them. Type "Jung Ma" into YouTube and you'll see dozens of videos of large-scale
PvP battles in the open world.
If people really
wanted World PvP they'd be out doing it and making it for themselves, regardless of what type of server you're on. They'd be out fighting, ganking, and duelling, rather than sitting on a forum complaining.
I'd personally recommend against rolling on the Fatman regardless of what aspect of the game you're looking for. The only reason the server was populated in the first place was due to rerollers (who have mostly left to play their original characters), which tends to create a more fickle community.