Since Week 4, defenses have successfully countered what Buffalo was doing well. As an offense, Buffalo is averaging less than 19 offensive points per game since playing Cincinnati. That's an indicateion to me that they can't counter what defenses are doing.
Like every team, Buffalo needs to adapt to what other teams are throwing at them. It's not as simple as going back to what worked, it's developing a scheme to be one step ahead of opponents. Teams will always take away your strength, and good coaches can tell by now what Buffalo can and can't do. The Bills need better talent on both sides of the ball, because coaching alone won't win games.