I believe RickJay is entirely correct re: automated pitch-calling. That’s exactly the job for high tech systems and the decision will be immediate. Let the human bean behind the plate decide the other stuff; did the batter swing or check it? Was he hit by the pitch or did he make an inadequate attempt to avoid it? But in determining whether or not the ball nicked the strike zone, a zone that will not change from AB to AB or even pitch to pitch, machines should be able to outperform man by a lot.
I agree 100%. You’ll still need a plate ump but not for strike zone calls.
You could let the ump signal the balls and strikes, too. Just put one of those things in his ears like they use on Impractical Jokers. It’ll still look like he’s making the call.
“And the ump is signaling to hold the pitching, it seems he’s having audio problems.”
Still worth it. 
Giancarlo Stanton’s gruesome face injury a few years ago was another instance - it was called a strike because he was judged to have offered at the ball that hit him in the face. Doug Mientkiewicz had a similar experience while playing for the Yankees - the umpire loudly shouted “no, you stay here!” when he started to trot to first.
Tottenham just beat Ajax today to advance to the Champions League Final…on a goal that was literally one second past the time stoppage time should have ended. (90+5, the goal was scored at +5:01.)