I'm not willing to judge the outcome of that deal 14% of the way through it. If he bounces back the next couple of years and is an important cog in a playoff or world series run, I'll be fine with it. If, because of that contract we're able to attract other key players, then it's a good contract. It's still too early to call it the worst deal in the history of baseball. That's too blunt an answer for a remarkably nuanced situation.
It's just money. A team can spend money, but they are OK as long as they don't trade away good ballplayers. Money doesn't hit or field all by itself. That's the problem with the Yankees. Look up Doug Drabek to Pittsburgh for Rick Rhoden.