“When you have two challenges, I don’t see anything wrong with the concept of ‘you can challenge any two plays that you want.’ I understand that judgment calls are judgment calls, but to say that an important play can’t be reviewed, I don’t think that’s really in the spirit of trying to get everything right and making sure the most important plays are officiated properly,” he answered.
This could get really sketchy. If you let all plays reviewable, then you could possibly have refs look over holding penalties on the line or pass interference penalties for possible replays and those are really tough to call. You could possibly get a holding call on every play if you wanted to.
There can be some tweaks done to the current system, but making the replay process available for all plays could become a huge cluster. There is always going to be a human element of error involved in these games and there is no real solution for it.