Sean Payton looked absolutely horrible with the Giants in 2002 and was stripped of playcalling. Went to Dallas to be QB coach after parting with the Giants. Went straight from QB coach to New Orleans Saints Head Coach.
According to that logic, we would be down a Drew Brees, several playoff births and a superbowl from 06-20.
Its often better to look at growth then it is looking for a pristine resume.