I'm not someone who complains about pace of play, but once the playoffs start, this is when the game really slows down. One thing I never understood that could shave a lot of time off the game is this: When you bring in a relief pitcher, he doesn't get to throw any warm up pitches on the mound. What's he been doing in the bullpen for the past 10 minutes? Why does he get another 5 minutes on the mound? When they call in a pinch hitter, they don't stop the game and let him take 5 minutes of batting practice at the plate.
The reliever warms up in the pen. If he gets the call in, he comes in and he starts pitching right away. No warm up throws. There's no reason for it. By doing this, you can have the teams bring in relief pitchers all day without slowing the game down in the late innings.