So, apparently the reason we haven't gotten PvP in Diablo III yet is because Jay Wilson is an idiot. Blizzard has been trying, unsuccessfully, to add "Team Deathmatch" which is just so fucking stupid I can hardly believe it. Anyway, they finally gave up on the idea and will be adding basic PvP functionality in patch 1.0.7 which is all the community ever wanted or asked for.
Link to the full article:
Jay Wilson is a Numbnut-420