For no umpiring position, save the one where the umpire calls from behind the pitcher, is free of problems. I know where it is. Maintaining one s balance requires vigilance for three hours. You ll observe that nearly all of the recent additions to the National League staff, supervised by Ed Vargo, use the scissors. Imagine a knee umpire trying to cover second base when the field umpire goes out.
Most observers say it looks lazy, and in the hands of an untalented umpire that is also true.
The practical objection is that since few umpires use that stance, it s difficult to find good trainers. The philosophical objection is that the umpire is farther removed from the low pitch. Box v. Slot was the court case at issue. The low outside pitch is the number one problem for inconsistency in ball strike calling. That is certainly true for slot umpires though not for those of us who use the box.