Folks, I think this settles it. For me.
Amazon:
http://www.amazon.com/Diablo-III-Sta.../dp/B00178630A
2/5 stars on amazon. 3112 reviews. That's bad, people.
And this:
http://www.gamespot.com/diablo-iii/u...t/platform/pc/
Diablo 3 - User Score: 7.2 (3840)
http://www.gamespot.com/torchlight-i...t/platform/pc/
Torchlight 2 - User Score: 8.6 (777)
Hell, I'll just keep going:
http://www.metacritic.com/game/pc/diablo-iii
Diablo 3 - User Score: 3.8 (7861 ratings)
http://www.metacritic.com/game/pc/torchlight-ii
Torchlight 2 - User Score: 8.8 (1210 ratings)
In almost every way, the initial industry reviews were equal. But the user scores ARE NOT. What this tells me is the initial feeling in the industry was positive, but things didn't work out for Diablo 3.
Know what I think happened? They tried to remake Diablo 3 into an MMORPG-hybrid. They wanted to take their experience with WoW and apply it to Diablo 3. Don't ask me why. Then they added the AH. Honestly, I don't know if it would have made any difference if they hadn't added the AH. Even when Diablo 2 was mainstream there were a lot of players buying items and characters through 3rd parties, but it wasn't something that was officially supported. Now that Diablo 3 officially supports buying things in-game, I think it has not only infected its development but the players themselves now feel they have to buy things to have fun. But whether this explains the discrepancy between industry and user reviews, I can't begin to say. Again, the whole meddling in the formula to Wowify it may have played just as much a role in the unimpressive user reviews.
Of course, I don't think Diablo 3 is shutting its doors. But I think this moment in history will be remembered by many as the moment in time when they could no longer trust acti-blizzard. These people will go elsewhere and play other games, like Path of Exile or Torchlight 2 or Grim Drawn. They'll take their $$$ with them.