The good news is that Diablo 3 is days away from being ready for release. The bad news is, Blizzard had to sacrifice PvP in order to do so.
"As we're counting down the days until we're ready to announce a release date for Diablo III," the company explained on the game's official blog. "We've come to realize that the PvP game and systems aren't yet living up to our standards.
As a result, Blizzard "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."
When the PvP patch is ultimately ready, it will add multiple Arena maps with themed locations and layouts, PvP-centric achievements, and a matchmaking system that will help players get into fairly matched games quickly and easily.