All the above are excellent, valid points (well most of them), with reasoned rationale and balance (now and again), but D3 is a rare case where all of the restrictions of the DRM, besides on a principle level, don't affect me.
Always-ways on DRM would normally be a deal breaker, but there's no single player, and I never wanted to play single-player, so as long as it saves my state, it won't matter to me, on a practical level, if there's DRM in the background, because if my nets down the games down. I won't use the auction house, and just play with friends, so that's that avoided. I don't want hundreds of characters, I'm not too concerned about not being able to call my character DickCheese McSlutdumpster, and I don't want to cheat. As for mods, while a bit of a sore point, I wouldn't use them in the first plays anyway.
So in conclusion, as soon as it hits a Steam sale or I see it for £20 somewhere, I'll buy and, likely, enjoy it.