I'm almost always connected the the 'net, so the always-on DRM, while annoying, isn't a gamebreaker for me.
What was a gamebreaker for me and D3 was the fact it was just a boring game with limited content and customization. If it were only $10, it would have been a good deal, but compare it to Torchlight 2, trumps Diablo 3 in almost every aspect - and is only $20... it's becomes much more difficult to say Diablo 3 is worth it.
I was in the D3 beta for months. I really wanted to like it, but I just couldn't. I avoided it, and I know many other people that have avoided the game because they played the final beta, or have seen one of their friends play it and saw how simple the game has become. I'm also seeing a lot of people that have regretted spending their $60 on a game. One friend of mine simply said, after playing the game was, "That's it?"