Morhaime notes that Blizzard "looked at historical sales for Blizzard games and other top-selling PC games and watched preorder numbers" to the server requirements at launch, even going so far as to add further server capacity beyond its estimates. Still, says Morhaime, it wasn't enough, noting that "we've never gone from 0 to more than 6 million players across multiple continents within a few days with a brand-new game." He adds that Blizzard will strive to do better with future releases.
Regarding player reaction to Diablo 3, Morhaime states that Blizzard is working hard to improve the game on all fronts. That includes more varied items and improvements to the auction house, social features and character balance.
Concerning the auction house, Morhaime says the primary reason for it existence is to give players "peace of mind" when purchasing items that would otherwise come from unsecured third party services. Furthermore, Blizzard wanted to create a way for players to benefit from their extra loot. Still, Blizzard wants to make sure players "have a great experience with Diablo 3 without feeling like the auction house is mandatory, which was never our intention."
As for the need for a persistent online connection, Morhaime says that it's more than a simple measure to prevent piracy. "More important to us is that the online requirement is critical for the long-term integrity of the game experience." Specifically, he notes that the requirement is tied to persistent characters, social features, security and even customer service. Despite the online requirements "downsides" Morhaime says "this was the best long-term decision for the game."
Finally, Morhaime says Blizzard is working on a new gameplay system that will give high-level players "new goals to strive for" as opposed to the unsustainable "item hunt."
Head over to the Diablo forums for Morhaime's full statement.