...its more about BYU potentially struggling due to some very basic weaknesses:
BYU's OC is unproven and untested. Brandon has publicly admitted he's been having issues keeping his emotions in check during the play-calling process. (Per a TrueBlue interview after the spring game)
BYU's TE group is unproven.
BYU's running backs are average to sub-par.
On Defense:
BYU's secondary is sub-par.
BYU typically struggles against any team with any sort of mobile QB.