This is in reply to the previous discussion, which was based on the fantasy scenario that BYU goes undefeated this year. The argument basically comes down to the following scenario (Team A vs Team B):

Both teams play a nearly identical 9 games (6 games against tough opponents and 3 against cupcakes) and win all 9.

Team A also plays an additional 3 cupcakes, again winning all 3 games, finishing 12-0 on the season.

Team B also plays 3 additional tough opponents (similar difficulty to the 6 tough opponents mentioned above), going 1-2 in those games, finishing 10-2 on the season.

In my mind at least, Team A would seem to be better in this oversimplified scenario, which would be BYU of course here. Given that a 2-loss P5 team often sneaks into the top 4, BYU should definitely be included over them. This scenario assumes that BYU's 6 toughest games (UW road, Wisconsin road, Boise St road, Utah road, Cal home, Arizona road) are equal to the 2-loss team's average conference slate difficulty (probably better given most are road games against possible top 25 including a couple possible top 5).

I can't see how BYU could be excluded for a 2-loss P5 team in most scenarios.