I'm late to this thread, but agree with Chief's suggestion, and thought the same thing before I read it here. The only other thing I think would be great would be a green light/red light signal in centerfield. Maybe even a yellow when calls are under review. If there is a close play, let the 5th umpire turn on the green light to confirm the call. It engages the fans and gives them the feedback we've all wanted but haven't gotten with replays not being shown in the park. Yellow light if under review, red light if the call is wrong. If no light, it's up to the home plate umpire, batter, and catcher to keep the game moving or suffer a slow play penalty under the current rules. A green light should mitigage that, though.