any system that loses the ability to exclude 'unworthy' 6, 7, 8 win Conf Champs is broken from the start, if there are only 8 total spots.
The SEC was the only conference that had two playoff worthy teams in their championship game, the rest of them were playoff worthy teams vs semi-bums who were just the least bad team from the other side of the conference.
If conferences want auto bids then they should have to change their format so they pick the actual best teams from their conf to to play in the championship game (not the best from each side where one side is often garbage) or just do away with the championship games and name the champ based on predetermined, known hard data points (ie conf record, head to head, overall record, common opponents, sos). But even then there should be a stipulation that if a conference champ does not have at least 10 wins, that conf loses the auto bid for that year (which gets added to the at large bid total) and for that conf to get in they must compete for the at large bid.