Personally, I'm going to wait until I've played StarCraft: Ghost before saying how I think StarCraft II will be. Since Ghost is supposed to be the bridge between Brood War and it's sequal, the ending of Ghost will definately give me an idea as to how I think StarCraft II will be, and if that ending is bad, well... You get the idea.
I'm also interested to see the storyline of Ghost. I loved StarCraft's original storyline, and it is the only reason I still like StarCraft. I haven't played the actual game in months. If Ghost has a horrid plot, my faith in Blizzard's abilities might faulter. If it's good, I expect nothing less for StarCraft II.