The worst thing about the missed calls is that they take the skill away from the best plays. The pitcher who paints the line is not consistently rewarded, and the hitter who holds off on pitches just outside the zone is also not consistently rewarded. This is the opposite of what we see in tennis.

This would seem to be a normal distribution of missed and correct calls on pitches that touch the line. The last study I saw concluded that umps
get about half of these pitches wrong.