[citation][nom]s3anister[/nom]I beat Wings of Liberty in 8 hours on normal and haven't touched it since. Starcraft 1 gave me many more hours of play than SC2 did.[/citation]
Try the game on Brutal; the campaign will last at least 3x as long. My girlfriend, who never played an RTS before, beat normal without too many problems, so you're not saying much by beating the game on normal in 8 hours.
I still don't get the "1/3" of game argument that I'm hearing over two years later. The game has nearly 30 missions, just like SC1. The campaign mostly lets you play as one race, but it is deeper, more diverse, and is probably the best-designed RTS campaign in the genre's history.
Heart of the Swarm and the next expansion will both cost $40, "priced as an expansion," according to Blizzard. This is how much their expansions typically cost, from the 90s onward. Seems fair to me.