It started with promise, didn't become miserable until he hired Tepper. I would have added "...another DC who can't get off the field on 3rd and 9" but Tepper defenses never put their opponent in that big a hole.
The issue with Miles is that yes he wins a lot of games. However he repeatedly makes the same damn clock issues in nearly every single damn game. His mistakes are often very costly. The D at the end of games is on Chavis for the first two but when it fails that often and you keep going back to it. That starts to fall on Miles as well as the HC. He is too damn stubborn. Also look at how LSU has become more run oriented recently. It was successful against UF but not so much against UGA or Ole Miss. Against Ole Miss we just kept pounding away(of course Mett didnt help that either).