"Inability to pass the ball" - Taylor finished 18th in passer rating in 2016, after finishing 8th in 2015.
"But passer rating is irrelevant!" - Okay...
"Taylor ended the 2016 regular season with the 10th-best overall grade among all QBs, at 84.7. That’s higher than Alex Smith, Ben Roethlisberger, Jameis Winston, Andy Dalton and—here is the big one—Dak Prescott. Last year, Taylor was seventh (88.3)."
https://www.profootballfocus.com/pro-bills-should-build-around-tyrod-taylor-not-show-him-the-door/