I'd prefer they get rid of replay all together. Replay has removed the exhilaration out of a big play. Now you have to wait for a booth review or coaches challenge to know the play stands. This will make that even worse.
I'd rather see them hire more competent refs and add additional to the field of play. Then put one ref in the booth as a head judge. If he sees something that's missed like the false start, he can make the call.
As far as PI, I'd like to see it judged more like the running into/roughing the kicker rule. Yes it's subjective but beats the old days where if the kicker is barely touched, he goes down like he was hit by a truck and it's an automatic 15 yard and 1st down. With PI, if it's blatant and the defender mauls the receiver, then mark it at the spot and maybe even add 10-15 yards. If it's just inadvertent contact then 10 or yards and 1st down.
Oh yeah, 15 yard unsportsmanlike conduct when the receiver or defender ***** at the ref when a call is not made. That includes the throwing the flag gesture