The NFL is highlighting the issue on both ends. With the over-reviewing, now no one knows what an actual catch is, similar to how offsides is being reviewed. On the other side, they are reserving the pass-interference reviews for the only egregious misses, which have led to plenty of decisions of clear pass-interference that the refs happened to miss, but it wasn't deemed too egregious.
It will be impossible to determine the sweet spot IMO. Even with a time limit, I could easily see a horrible decision being made and people complaining that they don't have enough time.