I hope you guys realize diablo 2 had an arena where you went to pvp too right? It's called blood moor act 1. No one actually fought outside near the monsters as well since that's just annoying and you'd just leave the game if someone hostile you while pve'ing.
While I think it would be a lot funner if pvp was open like darkfall the fact is diablo 2 was awesome without that(in essence) and diablo 3 probably will be awesome without it too.
