The referee situation in the NFL definitely needs to be addressed.
If it were up to me, they would have at least double the number of crews needed. 2 go to each game and the random selection of which crew happens minutes before kickoff.
There should exist a pool of referees, similar to a practice squad. These would be called up to replace refs who are suspended.
Referees get paid more money, but also risk fines for egregious or repeated errors. Continued bad calls may result in suspension and/or removal from the league.
Poorly rated crews don't work on bye weeks (so get no pay).
Top rated crews work the "booth" and make all decisions on coach's or automatic challenges.
Did I forget anything?