Baggage fees are the root cause of the boarding scrum. Mishandled baggage contributes to the problem as well. More checked bags would result in fewer bags in the overhead and less need to get on the plane first to fight for limited overhead space. Rearranging the boarding groups just makes some part of the group madder but doesn't solve the underlying problem.
It would be nice if we could actually see some return on those incredibly lucrative baggage fees that UA and other carriers are collecting beyond the pittance a free drink or snack costs them. Perhaps that would stem some of the hatred.