Change all the rules. PI is spot, illegal contact is 5 yards and no auto first. Expand replay. So it's 3rd and 6 LCB is beaten so tackles his guy on a double move and the QB throws the ball that way, but it sails harmlessly up the field as the WR is on the ground already.
Ref calls PI and 1st down. But defense can see he was tackled before the ball was thrown, so it's illegal contact, not PI. The ball wasn't in the air, it can't be PI. So they throw a challenge flag. They win, because it can't be pass interference unless the ball is thrown. Illegal contact isn't reviewable. no first down for you and they pick up the flag. Can't call a penalty on replay that wasn't there before. So not only do they get screwed from the front, they get screwed on the backend too LOL instead of 3rd and 1 it's 4th and 1 because they can't give them an illegal contact penalty from replay.
So fans have outrage because this was the Super Bowl and they change the rules to allow illegal contact to be reviewed too and then we're back to any touching past 5 yards is a flag, or isn't it? and more learning how to interpret the rules again and every year we recognize the game less and less. Thanks replay.
I think in your scenario it would be 4th and 6. Whatever, doesn't really matter. I think anyone can make up scenarios on both sides of the argument for and against replay. Depending on what side of the debate you are on, one makes more sense than another.
For me, its a matter of giving a coach a limited number of chances to correct a mistake that he feels could potentially have a big impact on the outcome of the game. Mistakes are made by officials during every game and they don't always balance themselves, as some like to think.
Whether you like or don't like replay and the rule changes surrounding it, the NFL isn't the only organization that has been kept busy trying to keep up with technology and the way it effects how things can be judged, refereed, etc. Pretty much every sport is making changes. Police vehicles and officers themselves are equipped with cameras. Some traffic intersections or speed zones are policed electronically; run a red light or speed, snap of a picture and you are mailed a ticket.
So why does the NFL have to make these changes? I don't think its necessarily just to improve the game, more than it is meant to quiet the backlash of what technology has shown the audience many times, mistakes are being made by the officials, mistakes that sometimes could be rightfully considered game altering. The media and fans see these mistakes replayed over and over, not just during the game, but for a long period of time after via just about every social media service known.
Which brings up my final point. Technology for decent instant replay has been around a pretty long time, but it wasn't until multiples camera angles, 24/7 sports channels and internet sites replaying all the blown calls and the media and fans taking up the debate on how each blown call effects the outcome, that the NFL has taken so much heat when a blown call impacts a game in what might be perceived in an unfair way. 30 years ago, a blown call....no big deal, in most cases it was forgotten about an hour after the game.
Now if you are a fan who doesn't want to see the mistakes replayed over and over, then you may want to listen to the game on the radio and stay off the internet after. If you think mistakes are part of the game because they balance out in the long run and replay is stupid, I think you are going to be disappointed watching Sporting events, replay is here to stay and will probably be used more and more in a variety of ways, in attempt to get the calls correct.