I didn't see this posted, but here are some (just the main changes, there are tons of little changes) of the changes to Wings of Liberty:
Wings of Liberty 2.0.4 includes:
- An all-new user interface with new menu screens.
- The launch of in-game Clans and Groups.
- New Replay features, such as Watch with Others and Take Command.
- A multitude of Editor improvements.
- New matchmaking options: Training Mode, Vs. AI Mode, and Unranked Play.
- Players Near You, so you can find other StarCraft II players on your local network.
- New customizable Observer UI."
http://us.battle.net/sc2/en/blog/8718598
I like that they're improving the social features (finally). Looks like a great update. My screenname is crazyorloco on it if anyone wants to add me. I like to chat on it. I'm not really good and my connection sucks, I play against the computer A.I. almost daily. I use to do this on the original starcraft too. I'll be moving to HOTS soon...