$17 million for Lackey seems crazy, but I guess that's the market. I would have preferred that the money be spent to upgrade the offense, but we'll see what shakes out.
I really don't care that much about the money. The fact that they were able to get one of the top 20 pitchers in the league, who has been remarkably consistent, without giving up any assets other than cash is huge. While they may not be the Yankees, the Sox still have plenty of money to spend, and one thing about Lackey is there is little reason to think he is going to be a huge bust. Now, perhaps he will only be worth $12 million, instead of $17 million. That won't kill a team like the Sox.
And with a rotation of Beckett, Lester, Lackey, (skinny) Dice-K, Bucholtz, and Wake ready for injuries, this team doesn't need the hitters nearly as much...particularly if they upgrade the defense.