This is just the case of another commissioner trying to make their "stamp" on the game.  It's not like Barry Bonds is coming up for every single at-bat, so the amount of time this will supposedly save is clearly negligible.

Solving replays and commercials would, by far, save the most amount of time.  I still don't see why replays can't be solved in less than a minute, or even 30 seconds.  On TV it's usually pretty clear, after a few replays, the camera will go back over showing the umps still standing there waiting for a call to be made, when you yourself already know the answer.