I, too, prefer single player, and I just finished a Normal run.
-Like the previous voice actor better. Her voice was girly-er.
-Why did they take 2 years? Sadly, just to make cut scenes.
-The Zerg aren't badly done, but they just don't have a fraction of the charm of the Space Rednecks.
-You have a tremendous amount of unit customization. None of which are really necessary on Normal single player. Swarming with your unit of choice is still your best bet.
-Kerrigan's still pretty evil. Hard to feel anything for someone after they killed their first million people.
-Overall, I'd give what I played a B-. It wasn't dull, the production values are first rate, but it honestly brings nothing new to Real Time Strategy Games.