Six weeks from today, the NFL will play it's first scheduled preseason game with the new replay rules for OPI/DPI. Thus far, it still looks like the league doesn't know exactly what they want to do. Things I've heard:
A replay official told me that his/her plan was to just grade the play live like they would film. If they would downgrade the official in film review for the call or non-call, then they will buzz to change the call. If the play looks marginal (read: possibly wrong but not worthy of a downgrade), let it go. This seems to me like the most reasonable course, but has been severely contradicted by other people and the NFL since I had this conversation a few weeks ago.
I've talked to several NFL referees (white hats) with various reactions. Some think it's a complete joke and will hurt the game, others are on a wait and see basis. Nobody was for it. Interestingly, they also say that the NFL coaches have told them that they hate it (with a few vocal exceptions). The coaches want the play fixed, but they don't want the responsibility of having to make a decision on challenges.
Lastly...some think that there are those in the league who intentionally want this to be a disaster. They are thinking along the lines of "Okay, you went around the normal process (competition committee) to get these changes in, be careful what you wish for". It doesn't seem plausible to me because you have to think that would cost Riveron his job, but then you see plays like this:
https://twitter.com/MikeGiardi/status/1141105682038439936
Here is a play where a TD is scored and DPI is called. When you look at the replay it's pretty clear that there is OPI and no DPI. The league is going to split the difference and call both? Talk about the worst of both worlds, you make the officials look incompetent AND you screw up the result of the play.