I think that Bledsoes success also became the impetus of his failure. He was put in a position early on where he had to put the team on his shoulders. In 1994 he wasn't a 'top' QB but he threw the ball 700 times, amassed some numbers and when the team starting playing good D down the stretch, they made the playoffs. By 1996 they got to the SB because Tuna had built a good team, and Bledsoe was being deemphasized. Parcells was harsh on Bledsoe about his mistakes, and Bledsoe himself described it as hating having to play for Parcells, hating the judgment and beratings, but realized it made him better.
After Tuna left, there was no one to yell at Drew for his mistakes. The fact that he was fan and media darling and now no longer the whipping boy of the coach, IMO, had him lose focus on elliminating the mistakes. At the same time both the coaching and talent deteriorated and now, once again he felt the pressure to carry the team. His play, and the success of the team went straight downhill.
Ultimately, IMO, Bledsoe became a psychologically damaged QB.
Had Bledose been drafted by and played his whole career for, Bill Belichick the result may have been very different. I think his attitude, commitment, and drive as well as basic skills coupled with being taught the QB position at the NFL level properly would have eliinated a lot of his problems.
I think that Drew had a ton of potential, flashed it, became overrated, declined, then became a mediocre journeyman. I would have liked better for him, but it is what it is.