[DC 86]

If I’m running MLB I have a strike zone that is mandatory. Mid-knee to the letters.  And I judge a home plate ump on how the game is called against that zone. 

You don’t get extra width. Or pitches below the knee.  Largely to compensate for the top of the zone being taken away.

Course, it’s not enforceable.  Umps have their own Union.

They already have that, and they even publish the grades, but as you said the umpires union is too strong, so there are no real consequences for having an inaccurate strike zone.

[DC 86]

If I’m running MLB I have a strike zone that is mandatory. Mid-knee to the letters.  And I judge a home plate ump on how the game is called against that zone. 

You don’t get extra width. Or pitches below the knee.  Largely to compensate for the top of the zone being taken away.

Course, it’s not enforceable.  Umps have their own Union.

They already have that, and they even publish the grades, but as you said the umpires union is too strong, so there are no real consequences for having an inaccurate strike zone.