HS,
Like many self-taught scholars, he was quite brilliant in some ways and amazingly stupid in others, because of the very fact that the body of his work was never challenged, let alone monitored.
I assume that you mean Fred Franz's work as a translator was not challenged or monitored within the WTS. I have no knowledge of that. His translation has often been challenged outside the hallowed halls of Brooklyn and there have been numerous discussions in the Watchtower, usually in the form of QFR, which have explained why a verse or verses have been translated in a certain way.
But I came across a most interesting article in The Christian Century (Vol. 68, No.19, pp.587-589) entitled 'How Bible Translators Work - Behind the Scenes in the Preparation of a New Verion of the New Testament'. It says:
A new version of the New Testament in English was published last year by the Watchtower Bible and Tract Society (Jehovah's Witnesses). This translation...contained a number of variations from the familiar translations of so striking a nature as to arouse the interest of scholars everywhere. It was reviewed for The Christian Century on November 1 [1950] by Steven T. Byington, himself a noted translator. Later, the New World Bible Translation Committee prepared an extended comment on points raised by Mr. Byington in his review, and at the request of The Christian Century Mr. Byington has written a reply to this comment. The exchange between the committee and Mr. Byington gives such an illuminating glimpse into the way in which translators of the Bible work that we are sure it will prove of great interest to the readers of this paper.
And there follows an "illuminating glimpse" into the scholarly considerations in translating the Bible. Byington also reviewed the translation of the OT (which was divided into four sections) for The Christian Century and commented in Vol.72, p.1146 on the second volume (Samuel to Esther) :
Yet continued experience has brought some changes. The translators have begun putting brackets around these words (not numerous) which they acknowledge not to be Hebrew but to be added for the sake of clearness. They have grown more careful to distinguish sentences where in Hebrew the subject comes before the verb from those where the Hebrew verb precedes the subject...though the committee has bound itself to dance in fetters, practice has taught it to dance more freely therein, and this second volume is more readable and vivid than the first.
So it would seem that some of the criticisms were taken on board. Whether they were internal or from correspondence it is difficult to say.
Earnest