Kyle Williams was a 6 time pro bowler and a 2nd team All Pro. Are you really using him as a comparison to Mack Hollins?! Hollins was an above average personality and an average at best WR. Would I want him on the team as a #6 WR? Sure. Would I lose a second of sleep if he is not on the team? Nope.
I don't know if there has been a more overrated player on the Bills. Reading the comments here, you would think he was a 1000 yard receiver. He was a quirky, edgy guy, but nothing more than an average backup WR.