Bloody hell, you're all a bunch of whining prats ('Cept those of you who aren't whining). A single campaign is not worth $60? Really? You're saying that multiplayer is worth thirty dollars?
Well, good for you. I'm glad that you've realised that after having no input into the game, having had none of your time taken up by developing said game, after not once being on their payroll in the past twelve years and not once being forced to buy this game that you get to have a massive say in what the final price of the game is.
I don't see the problem with this. Wings of Liberty was, by all accounts, awesome. It was a game that focused on the Terran story - a full game, judging from the sheer size of the campaign. Next up, we have a game that will focus on the Zerg story - A full game that focuses on the Zerg with an as-big or bigger campaign in it. And we have all that again when the Protoss game comes out.
Every game is standing up by itself as a full game. Blizzard have taken twelve years to develop this game; don't you think that maybe, just maybe, there might be $180 worth of content? You all seem convinced that the game will be the exact same as the original and thus only worth as much. If that's all, then why in God's name are you playing Starcraft 2? Go sit in the corner with your decade-old safety blanket.
Or you could accept that maybe this will actually be worth the three games it's coming as.