simple: he's messed up the QB position. he keeps rotating OCs every year in an effort to fix the offense to keep up with the rest of the pac, but i think it comes down to utah simply not being stable at QB. wynn, wilson, scattering of others in between. that's several years of mediocre/poor/out-with-injury QB time that is hard to overcome.
rotating OCs every year is something that is easier to do than finding a QB. but a good QB can make a bad OC look good. probably a major factor in mack brown being gone at texas too....you need a good (and mostly healthy) QB in football if you're gonna compete.