Here is my two cents, for what it is worth:
The WT has always had (at least post-1919) a fixation on the criteria which defines who is a member of their faith. In Russell days they didn't worry too much about it, in fact they were proud to say they didn't have a creed or clergy, but were just Bible Students. Then when WW1 came along, Rutherford et al were giving out signed affidavits to 'members' to the effect that they belonged to a pacifist religion and thus exempt. In their trial, Rutherford was challenged to prove these persons were 'members', and couldn't do so. The boys had subscriptions to the WT and their fathers were often elected elders of an ecclesia, but that was just about all the documentation they had. Rutherford and the associates went to jail for violations of the Espionage Act. They were later released and their retrial never happened because the war ended and the prosecution dropped it.
Ever since then they have introduced things which were created or invented primarily in response to US draft laws. It was all about the US draft and keeping the WT leaders out of jail. The Espionage Act is still US law even to this day.
Recording field service time = documentation that someone is a 'minister'
Doctrine that 'all Jehovah's witnesses are ministers', even young boys = a way to get young boys of draft age to qualify for a ministerial exemption
Invention of 'publisher' = documentation that a person preaches, thus is a 'minister'
Invention of 'pioneer' = documentation of 'full time minister' status
Central organization of control/appointment of elders, rather than local 'elected' elders = documentation of who has qualification to be a minister
Ministry School = documentation that a boy has 'ministerial training'
Books such as 'Qualified to be Ministers' = shows their fixation on documentated qualifications
Publisher record cards = written documentation preserved so as to give the boys something to present to the draft board
Baptism candidate, 80 questions pre-baptism and 2 questions at baptism = Despite claims that they didn't have a 'creed', the questions served as documention that the candidate had completed some course of ministerial study.
There's probably more I can't think of right now. Although over time most of these things have become part of the religion and have morphed into something else, when they were first conceived and introduced to the JWs, it was all about the US draft.
I came to these conclusions some years ago after reading the court transcripts of the 1918 Rutherford trial and the 1954 Walsh case.