The Mets have had Jon Niese for a while and Matt Harvey came up half way through last year. The two of them have thrown some utterly horrible games, some decent games, and some masterful games. Next, the Mets are going to call up Zack Wheeler and one of the best rotations that the Mets have ever had will begin to form.
This rotation won't be able to compete with the likes of the 69 or 86 Mets, but the three are very well capable of putting together outstanding seasons. As early as the 2014 season, if all three pitchers stay healthy the entire year, they could combine to win 40 to maybe even 50 games and they can amass 500 to 600 strikeouts.
After Harvey and Wheeler play a few years, the rotation would probably be led by Wheeler as the Ace, Harvey in the second spot and Niese would claim the third spot.