QRF is a bad metric to use on its own.It is good as far as rating formulas go. None of them are 100% accurate but if you just go look at the results of the playoffs over the last several years it's pretty accurate. Now the issue is 6A is a whole different thing and the way things work with relief section...ect kinda skews things. This is why in my examples I used AAAA-A as I think for most of the rest of the classes it's actually pretty good.
So if you don't like it for 6A, I understand that but it's not a bad formula to assist in seeding. Nobody should use any formula as the only criteria for seeding but I think it's a good piece of data to put teams in order then debate with other data to see if teams positions should be adjusted from there. You should also look at head to head and margins of victory and loss vs common opponents. However, when starting the seeding process if you order them by QRF it gives you a starting point.
I know for soccer they typically do use QRF and it works pretty well but it's not the only factor. Like teams close in QRF they usually will dig deeper into win margin and common opponents. But if there's a big gap they don't. It has come out pretty fair that way for soccer. This past season my daughter's team ended up getting a lower seed than than their QRF. They lost to the other team earlier in the year but had a higher QRF and same record but our team played a much tougher schedule. But the QRF was only like 5 points difference so the HtH overrode the 5 point difference. That seemed fair enough to me.
People will continue to use it anyways
One of the benefits of everybody makes it model is that it gets played out anyways.