Falcons fan here, so I've seen myself a whole bunch of Michael Vick The Pro Quarterback. I remain fairly convinced that his biggest on-the-field problem is that he's simply too freaking short to see over the line. He's a bonehead too, of course, but still -- the difference between Vick in the pocket and Vick rolling out has always been enormous. I just don't think he can see what's going on when he drops straight back. Because of that, I had about decided before this whole dogfighting thing ever went down that A) he was never going to be successful as a drop-back passer in the NFL, and B) that trying to win in the NFL without a QB who can drop back and throw effectively is a fool's errand. Maybe it's not impossible, per se, but it's like planning to finance your new business venture by going to Vegas and winning $100,000. It ain't likely.
Whether Vick can have a successful post-prison career depends on two factors. First, how much of a step has he lost? Not only has he been away from the game for awhile, but he's about to turn 29 -- old enough that he'd probably be losing a step or two anyway. Second -- and more important -- will he be willing to accept a reduced role as a sort of hybrid slotback/wildcat QB? He could be devastating in that type of a role, if he were willing to accept it and if he were picked up by the right team.
I don't expect it to happen, though. I expect him to insist that he's "not a wide receiver," to refuse anything other than being the guy with the ball in his hands on every play, and to be back out of the league within two or three years.