EverettMike
FIRE DON SWEENEY INTO THE SUN
agreed on both counts Mike: it's a good idea, AND mlb won't do it.
However, you do something like that and you'll need to put a limit on it otherwise you run smack dab into the issue that Patrice37 mentioned about the length of games. That's why i'm intrigued about the idea of an NFL like challenge flag, 1 per team. With the penalty i've mentioned. There are no TO's in baseball obviously, so that was the best we could come up with, short of something drastic like an additional automatic out or something.
There is literally no way it would have to take longer than a manager coming out, arguing, and either getting tossed or having the umps gather on the field to consider the call.
It certainly would be quicker than having the ump run into the dugout and looking at a monitor.