Redball reminds me a lot of Sean Payton circa 2002. Now, I am not saying that Garrett is going to ultimately become Payton so please, don't start down that path. He may end up seeing that kind of success but I doubt it will be in Dallas.
Payton, like Garrett, was a career backup in the NFL. Payton, like Garrett, was a QB Coach in Philly and then in NY. Payton, like Garrett, was promoted to OC from QB coach. Payton, like Garrett was considered to be a Wunderkind but while in New York, fell out of grace with his Head Coach. At this point, the story takes a different path. This never happened with Garrett. In the case of Payton, he was fired and later got on with Dallas under Parcells. This was probably one of the best things that could have ever happened to Payton. Parcells taught Payton about football and how it works. Payton was always a great offensive minded coach but he never understood the value of field position, turnovers and how offense influences defense and how both have to work together to win. I think that Parcells taught him this and also the value of detail in Coaching. He taught him how to be a HC. That has not happened to Garrett and as long as he stays in Dallas, it probably never will.
It is very unfortunate for both Garrett and the Cowboys because I do believe that Garrett will eventually be a fine HC in this league but not until he gets fired and moves on IMO. Somebody is going to benefit from the time invested in Garrett but I don't think it's going to be us sadly.