I'd limit the times you can step out of the box per plate appearance to once. I'd limit the time between the pitcher gets the ball back or gets the ball before he has to step on the rubber to maybe 10-15 seconds, and he can only step off twice per PA. Granted he could throw to first to regain his composure if men are on base, but he is risking a throwing error going over there. I think this could speed the game up quite a bit.
I know this would never happen, but they need to do something about the commercials, they are getting WAY too long.
One thing that I think would really make a manager earn is money is only allowing 2 pitching changes per inning. There is NOTHING worse than a pitcher coming into a inning, warming up (taking forever) being pulled after giving up a hit, getting pulled for another pitcher, he walks a guy then a lefty comes to bad so a lefty specialist has to come in, then he is pulled when the next right hander comes to bat. Hopefully the right hander gets some guys out because if he gives up a few more hits you're going to see another pitcher coming in. It's BS.
Being a Yankee fan and watching Torre his last couple of years there, I swear you would see 4-5 pitching changes a game, countless mound visits a batter or two before each pitching change.
Baseball is my favorite sport to follow out of the big three, but it is the hardest to watch.