Its a long season, and there is a lot of chess moves in the course of a season. Cincinnati didn't send extra rusher and dropped more people in coverage, especially against the short routes. The Bills needed to respond by hitting the longer routes, and a combination of inconsistency by Fitz on deep throws, receivers that don't have separation speed, and recievers who didn't make any big catches when needed, led to the demise.
However, the real issue with them is the ability of teams to rack up yards.
Although much blame should be placed on the secondary, I think some kind of pass rush, including this thing they call "a blitz," would help them. When a NFL QB has time, even a rookie, they will eventually find the open guy--and there will always be one open given enough running around time.
One way or another, the Bills have to figure out how to generate a pass rush!
The one lesson we have learned from the first four games, although improved, the front 3 or 4, are not capable of doing it alone. So the scheme has to change. Do something, figure out some way of putting at least a threat on the QB.That will help the secondary, which as we've seen, needs all the help it can get.