Over the last three decades, as that administrative time has skyrocketed we have seen virtually every civil service type test eliminated. The consequence is you bring people into administrative and management positions who are ILL SUITED to handle the intellectual components of their jobs.
Frequently those tests disappeared as part of a "consent decree" involving a faux civil rights contest. Since we already have EEOC to adjudicate civil rights complaints within the government as well as several other OPM processes that can rule in the same areas there's little need for any separate adjudication ~ with unions or otherwise.
Getting better trained and more capable supervisors is a great idea for the federales. It's long overdue ~ even at the top with the SES and the appointees above them, testing in subject matter related to the job would be a very good idea.
I know there are those who will claim that "testing" overlooks the opportunity to bring up otherwise charming and erudite individuals to management levels, but the cold, hard facts are that we already have far more than anyone's fair share of BS artists in the federal government at every level. Finding out if they have any practical knowledge is certainly worth the price.
You make all the right points I think.