The biggest mistake by the Bengals wasn't giving Marvin Lewis 9 lives. It was Paul Brown NOT naming OC Bill Walsh to succeed him as head coach. Instead of Bill Walsh building his dynasty in Cincinnati, he built it in San Francisco. The second worst mistake by the Bengals was Paul Brown dying and leaving the team to his son Mike Brown.
I haven't followed that team much. They've had a few good years, but not many of them.