Give Den Dekker another year and you might have a better player. The defense is already there, all he needs is a little better AVG and OBP. He does have speed and great defense already and way more power than Bourn.
Anyway, in 2014, Gomez is also a FA. Even more speed and would cost a lot less. Ellsbury is also a FA so it would be much better for the Mets to give another year to Capt. Kirk and DD and if that doesn't work out, go after a different CF from the FA list.