The problem is they lost to that 4th placed big 10 team. Did they deserve a spot because they were the best non-power 5 conference team or because they were undefeated? If they weren't better than the 4th place Big 10 team should they have been given a chance to compete for the title over them? These are things to consider and why I tend to lean towards a top 10 ranking as the criteria for a non-power 5. The best of the non-power 5 conference schools over the years have achieved a top 10 ranking (like Houston last year).
I don't think that 4 Big 10 teams would have gotten in if it were 8 either. They would have found a way to elevate USC over Wisconsin.
That is just wishful thinking.
The committee did 6 weeks of ranking. Until the last ranking, USC never broke the top ten.
They were wildly considered the biggest threat at the end of the year. There was no need to flip flop 8 and 9 because it made no difference. If a playoff spot would have been on the line they would have.
So what? You think that should be a deciding factor whether or not a team makes the final cut?