It is hard to believe that there was time when the NFL got rid of replay for a few years. Replay in football is absolutely necessary and more college and pro sports need to follow their lead. The only complaint I have is the NFL and NCAA should take the best of their systems and use one replay system moving forward.
Here is how I feel the system should work.
From the NFL game, take the following, referee looks at the play in a replay screen on the field and makes the call. The referee is supposed to control the game so he should be responsible for the replay calls, not the guy in the replay booth like in the college game. From the college game it is a no brainer to review every play and the booth can stop play if more time is needed to get the call right. It does not make sense to limit the number of times a play can be challenged. Every call should be reviewed, cannot have these games determined by a bad call because you do not have any challenges left. Also, the coaches still have the right to challenge any call they do not agree with. The argument is always that is slows the game down, but the numbers do not prove that at all.
Again the goal has to be to get the calls right, all of them!!
MLB, time to adopt replay on plays on the bases to go along with reviewing home run reviews. Too many plays at 1st or homeplate that determine games, a bad call should not cost a team a win, ever! NBA uses replay when it is needed and for them they probably use it the only way they can, assuming the NBA ever plays again.