RockPaperShotgun has detailed the ways in which Diablo III‘s online-only system will affect players, including being logged out in the middle of a game due to server problems or connections, a cooldown period, and no ability to pause the game.
You can’t pause. In fact, in most ways, the game acts like an MMO. For instance, quit it, and you’re given the optional cooldown to have your player clear the server properly. But it’s not an MMO. It’s not even close to an MMO. So when I’m playing the single-player game, and I’m in the middle of a frenzied mob, and there’s a knock at the front door, there’s nothing I can do. As happened to me yesterday. Twice. On another occasion I was surprised by a phone call that led to my having to do some other things. I’d safely left my character in a cleared area, but long between checkpoints. When I came back to the PC, I’d been idle for too long and the game had logged me out.
Being idle logs you out? No pausing the game? Dropped connections? This is Diablo, not World of Warcraft. No matter what the justifications for including an online-only Digital Rights Management system, or how many great “features” come with this connectivity, this is disappointing and unnecessary. This wouldn’t bother me so much if Blizzard wasn’t a leader in the PC gaming field, being copied by dozens of other companies; they set the standard for what games should be doing.
Of course, the real blame still goes to Activision.
I suggest you read the full post, as it explains even more annoyances with the system.