His skill level was sufficient for a team with two NFL-caliber WRs and a good defense. QB was also playing better last year. Or at least it looked like the QB was playing better last year...maybe the 2 NFL-caliber WRs were bailing him out more than was thought.
This year, his scheme also worked well against an average FCS team earlier in the year to which ISU was physically superior. But is seems for the typical P4 game, more advanced scheming and decision making is needed to compensate for the talent drop and less-good defense. Mouser may not have the experience to pull that off. If that is the case, the HC has put him in a position that he is not equipped for.