As we’re counting down the days until we’re ready to announce a release date for Diablo III, we’ve come to realize that the PvP game and systems aren’t yet living up to our standards. Today, we wanted to let you know that we’ve made the difficult decision to hold back the PvP Arena system and release it in a patch following the game’s launch. After a lot of consideration and discussion, we ultimately felt that delaying the whole game purely for PvP would just be punishing to everyone who’s waiting to enjoy the campaign and core solo/co-op content, all of which is just about complete.
I'm sure this will disappoint some fans but I think they're a vocal minority. In the history of the franchise PvP was limited to PKing and duelling outside town for the most part, not a big deal for most people playing those games.
Diablo 3 classes are not balanced for pvp and on the face of it the abilities wouldn't lead to a fun game unless adjusted. Who wants to be a chicken for 8 seconds, then feared, then turned into a chicken again?
They've altered skills and rune mechanics recently so all pvp development will have been impacted by the changes.
The positive side of this is that it indicates the game is very close to release. They're no longer putting new stuff in and tinkering. They're drawing a line under things and deciding that some of them won't make the final cut.
Hopefully we'll have a release date announcement next week or the week after.