Hiring Bob Diaco was considered a "good" hire at the time - easy B+ - dude won the Broyles Award as Notre Dame DC. However - he was a terrible fit with the current staff, was hired by the AD so Riley likely didn't even talk to him as much as he should. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.