Don’t look at me for an answer; I doubt that there is one that holds water. I venture to suppose that an iPad Pro has the number crunching capability to call balls - you need an up to call strikes - but as the use of the first/third base umpires illustrates, calling strikes is not best done from behind the plate. Put the home plate ump directly facing the batter - and far enough away that the risk of his being hit by a foul is de minimus. Or else use a TV camera looking down onto home plate to give the correct view of the bat.IMHO by tracking the pitch via video looking at home plate from the left and the right field “fair” poles and digital processing, a computer could track the path of a pitch far more consistently that a human can do it. Probably down to a millimeter or so.
If you really wanted to get serious about accuracy, you would instrument the fielders’ gloves and the bases so that the time when a fielder caught a ball, and the time a baserunner reached/left a base would be known to the millisecond. Tag plays would be difficult to instrument, but at least you could put a video cam in the bill of each player’s cap, and know what he saw.
Clearly replay officiating is still in its infancy; replays of multiple video feeds should be reviewable split screen so that it would be clearer what actually happened first. Instant replay should be, in the not-so-far-distant future surely will be, much faster than it is.
If you watch MLB now days, they have the computer generated strike zone. The umpires are probably correct 95% of the time, but why not 100%. Why not have a virtual strike zone that is set for each batter based on height. Seriously. You really don’t need the umpires in baseball. Screw George Will. YOu want umpires they can call a game in Little league through AAA ball. MLB should be perfect regarding the outcomes.