I am going to disagree here, I really believe Zimmer has lost his fastball and his Vikings teams were not playing well when he left. Dallas does not need someone old, who is stubborn in his ways, they need to hire a DC that can energize that group and help them perform against better competition.
Also the fact that Mike McCarthy & Mike Zimmer have a great relationship would also make me feel negative toward the hire. If I was Dallas I would try to promote from within and go with Aden Durde, who might give a jolt to the like of Parsons & DeMarcus Lawrence & Osa Odighizuwa.
The Dallas Cowboys need exciting & new, they do not need a clone of Mike McCarthy on defense, which is Mike Zimmer. So while maybe the Cowboys feel by hiring Zimmer, they keep Durde in his present role, however, Zimmer will not give the team the jolt they will need for the challenging 2024 as their Head Coach will be on the hot seat from day one and coaching for his job from week to week.