And that's how teams yo-yo.
You have to recognize that this isn't a normal coaching change. Most coaching changes come from a coach being fired or resigning before being fired. This is a coach who built a dynasty and has now stepped down/retired. The foundation is already built, it doesn't have to be torn down just to tear it down.
I do think the offense needs to be revamped. Whoever takes it over won't be Payton so the vision won't be the exact same. An offense with a few pieces in place already can be rebuilt in one off season through the draft, trades and free agency.