The current iteration of the NFL challenge system gives coaches 2 challenges, with a third granted if the first 2 are correct. But it also automatically reviews certain plays (all scoring plays and turnovers). While I don't think automatically reviewing all goals is a great idea (because not doing that is a big part of how we'll get away from the "toenail offsides"), the idea of having either automatic or referee-initiated reviews for a very specific subset of offences could easily be a part of a challenge system.Rugby league in Aus has one challenge per team per game. The referee also has the option of a review for tries. Not sure about the minor details but it seems to work quite well. That's not to say it did not have its own teething issues early on.
The current iteration of the NFL challenge system gives coaches 2 challenges, with a third granted if the first 2 are correct. But it also automatically reviews certain plays (all scoring plays and turnovers). While I don't think automatically reviewing all goals is a great idea (because not doing that is a big part of how we'll get away from the "toenail offsides"), the idea of having either automatic or referee-initiated reviews for a very specific subset of offences could easily be a part of a challenge system.
The entire concept of pass interference is a disaster - it's actually a surprisingly good analogy to our handball issues!The NFL also has limits on what can be reviewed. Almost all judgment calls are excluded (the experiment with challenges to pass interference calls was a disaster).
It may eliminate some toe nail OS issues, but not all. On any goal toward the end of the game, the coach has nothing to lose in throwing the review flag. It just means that only some goals will be reviewed for toe nail offside calls. I don't really see that as a big improvement.
IMO the challenge system is much better suited to episodic games such as odd ball and baseball. (But I still hate video review in general, in all sports. Luddites of the world, unite!)