The leaked announcement that John Fox and Marty Hurney will stay is as much a statement that there won't be a Bill Cowher type move as much as it is a sign of continuing with Fox.
Make no mistake, Fox is better than most options. Concerns of consecutive winning seasons are real, but overblown; his teams win. You don't get almost 20 games over .500 by just skating by.
But were the team to have not kept Fox, make no mistake. They wouldn't chase a huge money guy like Cowher. That'll command an eight figure salary, something the Panthers won't do. They'd more likely go get a lower salary coach who's deserving, than spend huge on a new coach while paying the old one.
And, were they to change to a younger coach, they'd have been unlikely to undergo radical change (a 3-4, for instance) to get a coach similar to Fox, and that coach would've been similar to Fox undoubtedly.
Media reports suggest that Marty Hurney was never really at risk of losing his job, though most fans suggested otherwise. I never saw him going (or being a package deal with Fox), at most I'd have expected him to become a VP/Football Operations and hiring a GM with pro personnel experience (an idea I suggested before 2008), which would give a similar situation now but with more beef in the scouting department.
In the end the team's biggest mistakes made (the Peppers contract fiasco, Delhomme's contract/non-benching) were both as likely made from the top as anything.