Perspective.
Prior to Riley, Oregon State had five head coaches between 1965 and 1996 -- all with career losing records at Oregon State.
97-245-7. That was the W-L-T total from 1965 to 1996.
Riley went 93-80 at OSU. That's nearly double the winning percentage of the 32 seasons prior to his arrival. In fact, he won nearly as many games in 14 seasons at OSU than the 32 seasons prior to Riley.
FWIW, Dennis Erickson had one very good season at OSU. 2000, when they went 11-1. The other three seasons, he lost either 5 or 6 games, which was right at Riley's average. Riley's 2012 season (you mentioned his last five being horrible), OSU finished ranked 19/20 in the two polls. Only two Nebraska teams in the past 15 years have ranked higher.