Most of them were D-2 caliber players. Diaco couldn’t recruit to save his life
Okay lets look at the rankings for both defense and offense when Diaco and Edsall were here I tried cross-referencing between NCAA.Com and the sports-reference.com site.
Diaco 2014, Uconn 86th in Total Defense | 125th Total Offense
Diaco 2015, Uconn 15th in Total Defense | 122th Total Offense
Diaco 2016, Uconn 65th in Total Defense | 128th Total Offense
Edsall 2017, Uconn 122nd in Total Defense. | 103th Total Offense
Edsall 2018, Uconn 130th in Total Defense | 112th Total Offense
Edsall 2019, Uconn 128th in Total Defense | 120th Total Offense
Edsall 2021, Uconn 123th in Total Defense | 129th Total Offense
(Take my analysis with a grain of salt)
I am not sure in 2015 Uconn was ranked 15th in total defense, but I think we can all agree that 2017 and 2018 was a step in the right direction for the Offense, but after Lashlee and Dunn left, our offense just went downhill. Diaco fielded a better defense than Edsall 2.0, but his biggest problem was his offense not being competitive and putting points on the board. So to the point of Diaco having D-2 caliber players, I don't think that was the case with him, it was really him being a defensive head coach not knowing how to have a competent OC. In all seriousness, Edsall had players on defense to be successful regardless being recruited by Diaco, but he tried to use a defense that Uconn was not strongly suited for and that really hurt the team.
I believe Uconn had some very talented players on offense, but our biggest problem has been finding a consistent OC and surprisingly, Uconn has figured out that with a competent OC we can be competitive. The solution for our current program is can we find a way to field a somewhat competitive defense at the same time if our Current OC can make us competitive in being able to score more points than the other team. I think what Mora has done differently than Edsall and Diaco is give the OC full autonomy of the offense. In CFB you can get away with a subpar defense if you have a very talented offense who can keep consistently scoring and driving the ball down the field.