At the Game Developers Conference, ex-game director Jay Wilson spoke at a panel, titled "Shout at the Devil: The Making of Diablo III" about Diablo 3's current state and its future. He stated that over 1 million players play Diablo III on a daily basis and that 3 million unique players log into Diablo III every month. Both are great figures, considering that the game has had more than its share of problems in the past.
Wilson also commented about the Diablo III's gold auction house and real-money auction house. He stated that both services had a negative impact on the game, namely because they both drive players away from the real goal of beating Diablo. He states that 50% of the players utilize the auction house, and find it the main motivating factor to playing the game. He says that Blizzard is working to return the game's emphasis onto the actual storyline.
Diablo III has done very well in the marketplace, selling over 12 million copies to date. The game was able to retain at least 25% of its audience, which is an impressive figure considering there isn't too much to do after you finish the game (except farm awesome, expensive gear). Blizzard may be able to draw a lot more of its customers back to the game once it launches its Team Deathmatch mode. Blizzard is trying to make the PVP system more entertaining by implementing objectives, rather than just making it a "whack each other" type of gameplay.
Diablo III should also be seeing a slight boost in its active players soon, at least once the game hits the PlayStation 3 and PlayStation 4. The new game has been modified to better operate on consoles. The console version of Diablo III will have all of the aspects of the current PC version of the game. There are Monster Power settings, Paragon levels, PVP (full version coming soon), and a lot more. It will also remove the Always-On DRM, and will offer 4-player split-screen co-op.
Diablo III should be seeing some major changes in the future. A few months ago, Diablo III's former game director, Jay Wilson, decided to leave his position to pursue new projects in Blizzard. He spent 7 years on Diablo III, but has decided to hand over the reigns to someone else. It'll be interesting to see the direction the new game director will be taking Diablo III, however until then, Jay Wilson has stated that he will still help the game in the transition process.