His first year as a starter he won a playoff game in Green Bay (02/03). Considering the team he had that was no small feat. I've watched football since I was knee high to a grasshopper. That was one of best performances I've ever seen. Just getting there was an accomplishment but to show up Favre at Lambeau in the playoffs was Herculean. His broken leg threw a wrench into his game after that, and I'm sure the present issue didn't just appear overnight. His focus has probably been marred by these off field issues for awhile.
Vick scrambling ability made it harder for conventional defences (like the Packers at the time) to handle. Once defences adjusted to take away the scramble, his abilities were limited. The key to contain Vick has always been stop his scrambling and make him be a normal QB. IF he could have been a better QB to go along with his RB abilities, he would have been devistating. Unfortunatly, as a QB, he was mediocre.