In a post on the World of Warcraft forums, a Blizzard representative has clarified the developer's stance on player-killing, griefing, and PvP for the recently announced Diablo III.
The Blizzard rep, posting under the name Bashiok, said:
"We're - in general - not big fans of griefing for any game. It's really only "fun" for one person, and that definition of fun isn't generally something we're going to want to encourage. It's far more positive to encourage and support meaningful and skillful options and systems within a game, than a mechanic for people to instantly turn against one another for no meaningful gameplay reasons."
So it seems that player-killing will be out, but what about co-op and player-vs-player gameplay?
"We have a large focus on cooperative play for Diablo III, and the mechanics and design decisions related to multiplayer are likely going to be based on supporting and encouraging it as much as possible, and not breaking it down.
That doesn't mean that PvP won't have its own focus, but those are details and features we aren't yet discussing."
Looks like Blizzard will be putting a World of Warcraft-esque PvE server ruleset into play, which allows for PvP, but only if both players agree to the fight. Will we miss griefing? Sometimes. Do we prefer a game without griefing? Yes.