I oversimplified my post but I agree with all that you are saying. I guess that gets to the crux of my pain with the selection committee. There are so many things that go into the selection so it would be nice to understand how they are arriving at the top 4 (especially in light of the small sample size). It's irritating that we are told "these are the top 4 teams" but we get no explanation as to why.I enhanced my original post to better explain what I was getting at.
To elaborate, opponents' winning percentage can only be useful if it also takes into the strength of schedule of their opponents as well. For example, playing a 9-2 Northern Illinois shouldn't yield the same strength of schedule as playing a 9-2 SEC or PAC-12 team.
To be useful, opponents' winning percentage calculations should also eliminate counting any cupcake games as they greatly skew the results. Home and away also needs to be considered.
The college football season has such a small sample size with little relative crossover that it's hard to build a really good mathematical model.