While CSP had a track record for resurrecting QB careers and finding UDFA gems and polishing them into starters, people forget that he had his playcalling duties revoked; but I thought that was under Jim Fassel and the Giants? Is that the demotion you refer to, or was it something else under Parcells? I honestly can't remember. But I do remember Parcells noted that CSP tended to "get the virus", referring to pass-happy tendencies and getting away from the run game.
I think the bigger takeway is that neither CSP nor Brady had "pristine" resumes. Both have/had impressive track records with much offensive success and MORE IMPORTANTLY, have stubbed their toes with setbacks, and grew from the failures to achieve again. I think THAT is an important distinction. I'm not interested in a guy who has never taken a hard punch. You don't know if he's got a glass jaw, or if he stays on the canvas. I want a guy who has been gut-punched HARD, and dropped to the canvas; only to rise again, take his count and shake it off, then throw his own retaliatory haymaker punch. I'd MUCH prefer the 2nd guy, with his blemishes, over the 1st guy with the perfect profile "on paper". JMO...