I would have to disagree with you on this. I think that in some of the examples provided especially the zenith pilot, the subdials are laughably disproportionately small. It's a lot easier to just increase the case size whilst keeping the same movement and fill in the empty space with large arabic numerals.
The caveat to this obviously is some of the examples just omit numerals instad of cutting them off.
I think some of the examples of cut off numerals are passable i.e. the archimede is fine, but I will agree that the A.Lange & Sohne Saxonia is quite bad.
Ultimately my opinion is that it comes down to the execution of each piece and that I can't blatently state that all subdials that cut off numerals are a design mistake equally as much as I can state that all subdials that don't cut off numerals are the better design choice.