Here is my shortened version of what Flutie did as A Buffalo Bill:
He energized the team, had some very good moments for the Bills, and helped sell tickets and establish more of a fan base, especially from Canada. Flutie was probably never going to lead the Bills to the Super Bowl, but he did a very good job for the Bills overall. Sure he is selfish, some teammates do not love him etc, but overall he was solid for the Bills.
One thing that I do find interesting: When Flutie lost his job as the starter after Rob Johnson's great game against the Colts (and Flutie was not all that good in 1999), so many people went nuts about how Flutie was screwed etc....but when RJ got hurt at Indy in his first year, and he had some good games to start that season (especially at home against San Francisco), but he was never given a chance to get his starting job back when he was healthy, but sure Flutie was winning (also a big part in that 98 run was the improvement of the defense), so nobody talked abour RJ not getting a fair shake.
That really shows how popularity for a player can alter one's thinking about a situation.