Was thinking about this a little bit more and while the Drury trade looks worse in light of the FA market, the Diaz trade looks a lot better.
Diaz's replacement is Galvis and I don't think Galvis is much worse, he's simply just a glove first player. Galvis probably even compliments the team better anyway because he provides a different set of skills than what Gurriel provides. Gurriel and Diaz are pretty similar players.
So we traded 4 years of Diaz for 6 years of an interesting big league ready pitcher. And we replaced Diaz for cheap with an equally talented guy who is a better fit. I hated it at the time but it was actually a nice trade!