I'd rather Steam get back to the core business of selling games, rather than trying to be some sort of oddball social network.

Drop the achievements (do a large number of players actually pay attention to that?), drop the trading cards (I still don't know WTF those are for). Drop everything that isn't about selling a game to a player. Then hire some competent UI people to simplify and clean up that abhorrent interface that tries to do too much.

In fact, separate Steam from Valve entirely. Let Valve focus on producing games and let Steam focus on selling them, but put a wall between them.