Brian Kelly's big mistake during 2010 was trying to turn Dayne Crist into a spread running QB, with a lot of designed QB runs. With all of that talent in the receiving corp (Floyd, Kamara, Jones, Rudolph, Eifert and Riddick), it would have made much more sense to put a heavier emphasis on the downfield passing game, which was Crist's strength.
I honestly believe that if today's Brian Kelly could do it over again, he would have done the right thing, instead of trying to make it "my way or the high way."
Despite all of that, Crist still put up some decent numbers in 2010 (almost 60% completion rate, 15 TD, 7 INT) in 9 games until his knee got busted up by that late hit against Tulsa on that QB run... I don't think he ever mentally recovered from having two fully blown out knees after that.