Hi Socks,
I am very familiar with that letter. I quote part of it in my book, Undertow.
In 1978 when VPW mailed the letter to Way Corps, I did not personally know any of the individuals mentioned in the letter. I knew them from afar. At the time, I was not involved with research, I was out on the field far away from HQ, and it would be five more years before I returned to HQ to work on the research team. So when I read the letter, I swallowed the party line and asked no questions. I accepted that these guys were disloyal and tricked by the Devil into questioning VP's research and disagreeing with how the Corps was being run in Emporia.
I suspect that the guys who challenged VPW mistakenly believed his claim, as many of us did, that TWI was a "research" ministry open to correcting mistakes and "changing as we learned more." From my experience, I don't believe it was. I think it was an organization VPW used to promote himself and his views on the Bible, including plagiarized materials.
To me, in the letter VPW sounds very paranoid that anyone might know a thing or two that he doesn't. He's mad to find out he might be wrong.
In 1984, when I returned to HQ to work on the Aramaic Concordance with the research team, that letter's contents came back to haunt me. In Undertow, I portray my own discoveries of corruption, Scripture twisting, etc.