He did? His best record was 10-4. The previous coach, Dennis Erickson, had a best of 11-1 and went 8-5 the year before Riley was there. Which also happens to be better than the majority of Riley's seasons. Riley didn't take them anywhere that Erickson hadn't already. Erickson actually won a Pac title while Riley topped at tying for second.
I agree with you that he'll run a clean program, but they downgraded in coaching talent. And Pelini wasn't a world-beater.