I think Jimmy G is much less of a certainty than people around here want to believe.
My opinion considers:
1) I devalue a players sitting on the bench and barely playing for 3 years
2) I don't consider the little bit he played as proof of his future, and frankly if you discount the first half vs Miami, most people here were extremely concerned about him being able to win while Brady was out. I don't think a half answers everything.
3) I think its a proven fact that NFL teams prefer to draft a rookie and develop him in their system rather than trade for a guy who was brought up in someone elses. (I also see no evidence that would lead other teams to put higher value on being Bradys backup, which some people here feel will happen)
4) Jacksonville has a QB they drafted 1 overall, and have been building their team around, who had a bad season, after being considered the reason for optimism. They jettisioned a pathetic coach, the next one will have the chance to work with their franchise QB, not have him cut so they can use another #1 on an unproven guy. Cleveland is more than a QB away, and there are many options to them that aren't Jimmy G.