Blizzard has announced on the Diablo III blog the game will not ship with the PvP Arena system. Instead, it will be released in a patch following the game’s launch.
"We’ve made the difficult decision to hold back the PvP Arena system and release it in a patch following the game’s launch," wrote lead designer Jay Wilson. "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.
"While we work on making sure PvP lives up to its full potential, we hope you’ll find some consolation in the fact that soon, you’ll be having a blast leveling characters, finding items, learning the classes, and perfecting builds…and that when the Arenas do arrive, you’ll be all the better prepared for battle."
When the PvP patch is ready, it will add multiple Arena maps "with themed locations and layouts" as well as PvP achievements, a matchmaking system, and a personal progression system which will reward the player for "successfully bashing in the other team’s skulls."
The post went on to say the team will be focusing post-launch efforts on making sure the Arenas are "as brutal, bloody, fast-paced, and awesome as we know they can be."
Wilson ended the post noting that Blizzard's putting the finishing touches on the campaign and co-op experiences for launch.
Diablo III is slated for a second quarter launch, with various retail outlets touting an April release.