Its crazy that somebody might win that division with a record under .500. I wish they changed the rules so that teams under .500,can’t make the playoffs.
In college football, I think teams have to win at least 6 games in an 11,game season, to qualify for a bowl game. The NFL should do something similar so that undeserving teams can’t win a weak division and slip into the playoffs.
Unfortunately this season, the NFC will likely have only have ONLY 5 teams finish with winning records (Carolina, Arizona, Green Bay, Seattle and Minnesota). It is not likely that the currently 6-7 Falcons or any of the three top NFC East teams (Redskins, Giants or Eagles, will win out and end the season with a 9-7 record, so it will be guaranteed that one team in the NFC playoffs will have an 8-8 or worse record.
The AFC isn't much better with just 6 teams currently having a winning record this late in the season. Only in the AFC, one of the three top wildcard contending teams (Kansas City, NY Jets or Pittsburgh) will likely miss the playoffs with 10 or 11 wins while the AFC South Champion will likely make the playoffs with an 8-8 or worse record.
Your idea would work in the AFC where the AFC South winner would not qualify for the post season, leaving the left out AFC Wildcard contender getting the final playoff spot.
It would not work in the NFC where there will only be 5 teams finish with winning records and no other team with a winning record would be left out.