Maybin wouldn't have carried the Bills on his back into the playoffs. Regardless of his sack numbers with the Jets, Maybin is still a single down specialist and one trick pony. His opportunities to get on the field playing for a team playing from behind all the time would be quite limited. How many threads have there been about the Bills never blitzing? Contrast that to the Jets that use blitzes in obvious passing situations all the time in order to get their speed rushers free and unblocked. He's had some success with the Jets in a very specific role and a situation that has utilized his only asset and that, from all indications, wasn't going to happen in Buffalo. Besides, Shawne Merriman was going to stay healthy and carry the Bills defense at the same position.
PS: That doesn't mean Maybin could not have been a bit of depth on a team with none and utilized (maybe even constructively) especially after Merriman succumbed to his annual season ender.