Dueling will finally be coming to Diablo III. However, the planned Team Deathmatch has been canned.
Diablo III director Jay Wilson took to the game's official blog to announce that the planned Team Deathmatch portion of PvP has been shelved. Wilson explained that after fleshing out the idea for Team Deathmatch that the development team didn't "feel the current mode is good enough."
He then went on to explain that Team Deathmatch had an issue with depth and class balance. Blizzard's play tester stated that though the mode was entertaining, without any objectives outside of pure fighting, Team Deathmatch became relatively boring after a few hours. And since Diablo III was, according to Wilson, designed to be a "PvE-first kind of game, where we never compromised on player abilities in the name of PvP balance", balance obviously became an issue. Wilson believes that the Team Deathmatch mode would benefit from a "laser focus on class balance" that would ultimately hurt the overall game.
As a result, Team Deathmatch is something that Blizzard probably won't be bringing back to the table. However, the development team is going back to the drawing table to rework out PvP.
In the meantime, Diablo III will finally be getting dueling. Wilson's post stated little about the particulars of dueling, outside of the fact that it's going to be launching with patch 1.0.7 and that it's slated to hit early 2013.
"We'll be providing details about that feature very soon," he writes. "So stay tuned."