However, they were in the Super Bowl last season. With the addition of their two #1 draft picks on defense, they were supposed to be even better. This was enhanced with additional veteran free agents.
What went wrong?
I think they may have underestimated the value lost in veteran leadership and experience when they let some walk and replaced them with rookies and other young players with talent but less experience.
When you combine that with both sides learning different systems under different OC's as well as the injuries to valuable O-linemen, you could see the potential for them to get bogged down a little.
However, it would be a tragic error to think this is a long term issue or that they are suddenly impotent as a contender.