I can honestly say that I am very excited for the expansion. It takes a lot of what I disliked about the game, and gave me what I wanted to see.
Can't say I'm really bothered about the "social" side of the game. I play it with my friends. We jump in and out of games and trade items as we find them, that is my social side concerning Diablo. However, I thought the fact that Blizzard will be adding clans to the game would be a good addition to the social side of things. They haven't revealed everything about it yet, so it is difficult for me to say whether it will be good or not, but I think it has lots of promise.
Also, I'm not going to go into the economy gripe people seem to have. No items can be seen as waste in the game, not as long as you can salvage stuff. With the addition of the mystic and the fact that the AH is leaving, the game is going to be very different, so I'd like to wait and see how it goes. But like I said, I played with my friends and my gear is self found, so I doubt my playstyle is going to be affected a whole lot.