The eye in the sky is the answer - the issue is they need to use it consistently when warranted. I've said the same thing as above, it should be very simple to decide when to engage - if millions of people see immediately on 1st replay from their couch there was a gross error then step in and correct it. The problem right now is how random the eye comes into play - it's ridiculous that is exists but is not used in so may obvious situations (using the couch metric). Get rid of the stupid challenges and stopping the game with refs staring at tablets - if done correctly the eye doesn't slow the game down and most blatent missed/wrong calls are corrected seamlessly not interrupting the game.