I hope they didn't learn too much from WoW, because WoW maintenance is a bit ridiculous really. Compared to a game like Rift that has pretty much zero maintenance, I don't see how WoW should take as long as it does and as often as it does. Diablo is not WoW and diablo has a significant solo component to it, frankly requiring someone who wants to play a solo game solo to be connected to a service with so much down time is kinda silly.