If this system was in place last season then the I'm guessing the State Champions still would have been MC in 8A over Oswego, BR in 7A over either Batavia or Hersey, Fenwick over ESL in 6A as the game was played that night not in a do over, Franny or PC over whatever Public team they eliminated to get there in 5A, and Montini over Rochester in 4A......so no difference outside of Rita who won overwhelmingly over Hersey and Batavia not getting the chance to play BR or at least being named runner up and the same for Franny or PC. In 8A it kind of went like that this pass season as MC beat LA in round 1, but I wouldn't count on either team having too many 4 loss seasons in the upcoming years.
This system will not stop Private schools from winning their respected classes, it will only eliminate a school that may have very well made the Championship game get eliminated 2 rounds sooner. All this does is guarantee at least one public school the chance to win a Championship which last year was the case in all but 2 classes.
If the Public school wins, all is right with the IL football universe, if they lose, the complainers will continue to complain. So would this system really fix anything? I don't think so. It will make the Catholic League side of the Prep Bowl really competitive!
You can't assume changing the system keeps everything the same. MC and BR likely still win, but their path and the paths of non-public teams in other classes would be different.
If, for example, they use the system I think they would, take that for what it's worth, here's how it could have looked last year. In my example there would be a max of 4 non-public teams per class, 4 play in the first round, the two winners play in the second round, and the winner gets the spot in the quarters (elite 8). Open to hear ideas on how this may otherwise be set up.
In 6A for example, there were 4 non-public teams and if were made to play in the first two rounds there's no guarantee Fenwick beats Naz again or if Naz has to go through Fenwick and St. Lawrence in the first two rounds do they still beat Lake Zurich in the quarters?
In 5A, there were only 3 non-publics so would Franny get a bye into the second round while Provi and St. Pat's play in the first round? If Provi were to beat Franny then PR likely makes the final.
Everything very well could have turned out as you said, but once you change the system, there's too many variables.
Nothing to get too excited about yet as this hasn't even gone to a committee vote yet.