If the pitch trackers on TV are accurate then an ump could have an earpiece that buzzes when there is a 'looking' strike. The umpire is still responsible for swinging strikes, tipped foul balls, out at the plate, etc. (everything that are responsible for now except looking strikes. What always bother me about umpires setting/interpreting the strike zone is illustrated by how annoyed I used to get watching Ricky Henderson bat. He was 5'10'' but his crouch gave him a strike zone that was comparable to Eddie Gaedel and he benefited from a lot of undeserved walks. If the strike zone size were set based on the batter's height, which would be easy to do electronically than with the human eye, then it level the playing field.