These are 3 players I found with very little trouble along with the ones listed by others on this thread. Conservatively we can estimate that the Bills have thrown away 1 quality player every 5 years. What difference would that make? Take Anderson for example, he played from '82-04. In that 23 year period how many games did the Bills loose? If those games were added to the win column through the contributions of this cast-off with a career 80% accuracy and a career long of 55yards, how would that have affected the Bills records? How many years would they have made the playoffs? How many times would they have had home field advantage? Would they have advanced further? Now don't start whining for me to answer for you. This is your homework, time to get off the lazy dismissals and start looking objectively at the performance of the team you root for.
After you have examined the impact of this 1 diamond in the rough would have had on the team, begin to consider the added impact of the other players (1 every 5 yrs est.) especially if 1 or 2 of them are still playing when the next diamond is polished and begins to shine. Then you will realize the secret of consistent SB contenders.
As to the case of Bell in particular, this is an obvious example of casting off a big (6-8, 318) diamond without exerting even a little elbow grease. Again: the definition of insanity is to do the same thing over and over but expecting a different result. If you are satisfied with going 7-9 eternally, don't bother with the homework just keep following blindly.