Oh my goodness. I cannot even begin to comprehend, let alone describe how excited I am for this game's singleplayer. Granted, I am comparing it to the Wings of Liberty singleplayer which was about as much fun as projectile vomit, but I really am liking the developments in terms of story which are coming about.
The multiplayer I'm a tad skeptical of. These are some pretty huge changes which ought to do some very interesting things to the game, though I suppose Blizzard hasn't buggered up balance yet, so I don't see why they would now.