Instant replay has become just another part of the NFL and therefore is being scrutinized more than ever. It's not perfect, but it has certainly helped correct some incorrect calls in big games.
However, don't count former NFL head coach and current Monday Night Football analyst Jon Gruden as a fan, per Men's Fitness (via Pro Football Talk's Michael David Smith):
I would eliminate all of it. Everything’s disputed now. Was he inbounds? Was it a turnover? It’s taken the juice out of the stadium. There are too many timeouts. Let the people on the field officiate and hold them accountable. Look, there’s going to be some bang-bang plays that have to be officiated. And who’s going to make the decision? The instant replay man in New York City?
Gruden is correct in that it does slow down play, and calls are still disputed. But it's not like they weren't before replay became so prevalent. At least with slow-motion replay, most of the time we can see if someone was in or out of bounds or if he lost the ball before his knee touched the ground.
If a play were to decide the outcome of, say, the Super Bowl, it's safe to say the winning team is going to be OK with the game coming to a stop for a little while.
ESPN Radio's Dan Le Batard agrees with Gruden. On his radio show Jan. 19 he said there is "hyper-examination" of play:
ESPN Radio @ESPNRadio
VIDEO: @LeBatardShow: #NFL instant replay is ‘extremely annoying’ @Stugotz790 @ThisIsFusion @ESPNU @gregcote https://t.co/HedfJzWYEl1/20/2016, 2:30:09 AM
He also said on his show he was conflicted because he wants the referee to make the right call, but it's hard for the replay process and speed to "coexist." Apparently Gruden doesn't care about any potential missed calls and is just fine with leaving it up to human eyes, which inevitably will make mistakes.
There have been plenty in big games—like a no-call on a Jerry Rice fumble on the game-winning drive of a 1999 NFC Wild Card Game between the San Francisco 49ers and Green Bay Packers and a touchdown run in December 1998 by Vinny Testaverde that was actually short of the goal line. It eventually led the NFL to bring back instant replay after it had removed it from the game for seven years.
Of course, incorrect calls can happen even with replay, but if technology is available, it should be used. If Gruden thinks there's controversy now, just wait until social media gets hold of a clip where an official blew a call in the Super Bowl.
That controversy would live in infamy forever.