He also talks a little bit about how Blizzard works as a team -- everyone working on the game has the power to veto something if they don't feel it works right, which is probably why we haven't seen things like player housing yet. It also explains why Blizzard takes their time -- when anyone can step in and say, "This isn't working" at any time, you get a lot of iterating and a lot of unreleased content. But as Pardo says, it pushes the whole team to do it better -- he can go to the people he'll know will have a problem with a certain mechanic and work with them to make it right.
Finally, they chat a little bit about whether, as Raph Koster is quoted, "the singleplayer game is an aberration." Pardo calls out Super Mario Galaxy's co-star mode as an example of a terrific singleplayer game that incorporates multiplayer in an innovative way, and says that singleplayer isn't gone forever -- it's just going to look a little different.