Reality is that those of us who said that we expected a 10 win season MINIMUM and an ACC coastal title weren't being objective. I realize it now. Diaz took over a 7 win team (7 wins with a potential HOF coach!) with no QB. As a matter of fact, our current starting QB was 3rd on the depth chart and was likely transferring. Even the much ballyhooed 2017 team was closer to an 8 win team than a 10 win team (took two miraculous catches against not great competition).
In the 21st century, I think only one 1st time HC (not a head coach moving from one program to another) at a P5 improved a team by 2 or more games over his predecessor and won his division- Gus Malzahn. That Auburn team was less than 3 years removed from a national title so he wasnt exactly inheriting a team with a broken culture. To expect Diaz to be just the 2nd coach in the 21st century to accomplish that feat is unreasonable, especially given that the 2018 team was an offensive disaster and the QBs had virtually zero coaching.