The close calls that are blown have been multiplying and there is no chance that they will overturn them. They should be able to challenge a call of their choice on any platform. If the National Football League has the priority to change a call then any decent umpire or coach should stand for yes
Instant replay is used in many other sports, and for good reason. Using instant replay will lead to both better audience and player satisfaction as disputed issues can be reviewed so that the correct judgment can be made...every time. I personally know many MLB fans who have become quite frustrated with inaccurate referee calls.
Even though the umpires do the best they can, they can't see all angles. The lack of instant replay means that certain plays get called wrong in the heat of the moment. Instant replay would relieve some of this pressure as long as it was limited and used only in certain cases.
I think if the game of baseball or any sport was played for years without the option to view an instant replay then it does not need to be used now. Just because we have more technology does not mean it makes everything better. The game loses it's excitement each time a call is delayed because the video has to be reviewed.
The last thing MLB needs is more instant replay. The games are already very long and drawn out. Using instant replay more is not going to help that. Baseball isn't a sport that needs to be using a bunch of technology in my opinion. It is a purist's sport and will do fine without it.