he's hated by fans of just about every school he's worked for since his success with ND, comparable to how most people see Gene Chizik atp. the corny interview stuff wouldn't matter if he'd been good at his job for more than a year in the last decade-plus.
from 2014-2016, he compiled the worst record for a UConn HC since 1920.
in 2017, he was hired as Nebraska's DC and torpedoed their DFEI from 46th to 98th.
in 2020, he brought Purdue down from 75th to 86th despite a huge talent upgrade.
the one exception was a decent performance as LA Tech's DC in 2019 that got him the Purdue job, but that's a lower level of competition.
edit: remember that David Hale tweet listing the experience of BB's staff? next to Diaco, it just says "is Bob Diaco." that's the level of known incompetence we're dealing with.