Dice-k was painful to watch, but 3 of his 6 years were pretty solid overall. He pitched 150 innings of 4.6 ERA ball in 2010, so that's barely screwing up the rotation.
I think there are several players on the Red Sox roster in the last 3-4 years who had worse contracts. Bobby Jenks was paid 12 million for 15 innings of 6.32 ERA, a drunk driving scandal and a lawsuit against the team's doctors. While Dice-k was paid 2 million per win, Jenks was paid 1 million per inning.
The Crawford signing single-handedly destroyed the franchise. When he had his Red Sox press conference, he was so nervous he couldn't put two words together. He handcuffed the Red Sox financially, so they wouldn't budget more starting pitching. He provided less on-field value in two years than Daniel Nava did in one.
Oh, and Lackey.