I would agree, he did have the talent. And same thing happened with the Jets.
I do not recall who it was, but someone on the NFL Network was discussing the "Rex Defensive Genius" is a huge stretch. In Baltimore, he had Ray Lewis and company--any coach would look good with them, in NY he inherited Mangini's defense--it was still good for two years, but in time Rex's influence was to take it to the middle of the league. Just like he did in Buffalo.
I hated the hire from the start. But as a fan, I was willing to give it a chance. He stayed too long in my opinion.
I would agree, as long as there is a viable alternative.