Give skilled position players the option to play with a flag. Penalty if you tackle someone with a flag. Tradeoff is that it's harder to get yards after the catch, but dramatically lower risk of injury for these critical players.
I would expect nearly all QBs to use this option, and many older and more injury-prone players.
At the start of this season we were talking about how much greater AFC teams and AFC QBs were than the NFC.
Now, the top 2 teams in the league are NFC teams. An NFC QB is the favorite to win the MVP award.