Hi Slim, interesting (and provocative!) thread.
I am going to somewhat disagree, I have long thought that the Watchtower insistence on the use of the divine name is one of their weakest arguments, and I am surprised that it doesn't cause them bigger problems. This is because it creates a contradiction with another important Watchtower doctrine, one that they share with most evangelicals, that the bible is inerrant and the NT manuscripts are a reliable copy of the original writings of the apostles and other NT writers. Take as an example appendix A3 of the revised new world translation:
https://www.jw.org/en/publications/bible/nwt/appendix-a/how-the-bible-came-to-us/
The Author and Originator of the Bible is also its Preserver. He is the One who caused this statement to be recorded:
“The word of our God endures forever.”—Isaiah 40:8.
That statement is true, even though no original Bible manuscript of the Hebrew and Aramaic Scriptures * or of the Christian Greek Scriptures has survived to our day.
...
How confident can we be that the thoughts contained in the original Bible texts have been accurately transmitted to us?...
Regarding the Christian Greek Scriptures, or so-called New Testament, Bible scholar F. F. Bruce wrote: “The evidence for our New Testament writings is ever so much greater than the evidence for many writings of classical authors, the authenticity of which no one dreams of questioning.” He also said: “If the New Testament were a collection of secular writings, their authenticity would generally be regarded as beyond all doubt.”
However in appendix A5 they are forced to take the argument that the manuscripts are not as reliable as they have just claimed they are in order to defend their insertion of Jehovah into the NT of the NWT:
https://www.jw.org/en/publications/bible/nwt/appendix-a/divine-name-christian-greek-scriptures/
Bible scholars acknowledge that God’s personal name, as represented by the Tetragrammaton (יהוה), appears almost 7,000 times in the original text of the Hebrew Scriptures. However, many feel that it did not appear in the original text of the Christian Greek Scriptures. For this reason, most modern English Bibles do not use the name Jehovah when translating the so-called New Testament. Even when translating quotations from the Hebrew Scriptures in which the Tetragrammaton appears, most translators use “Lord” rather than God’s personal name.
The New World Translation of the Holy Scriptures does not follow this common practice. It uses the name Jehovah a total of 237 times in the Christian Greek Scriptures. In deciding to do this, the translators took into consideration two important factors: (1) The Greek manuscripts we possess today are not the originals. Of the thousands of copies in existence today, most were made at least two centuries after the originals were composed. (2) By that time, those copying the manuscripts either replaced the Tetragrammaton with Kyʹri·os, the Greek word for “Lord,” or they copied from manuscripts where this had already been done.
I am struggling to think how one can reconcile these two competing positions, and I wonder if you are aware that the Watchtower Society has ever made an attempt to do so? You ask:
However, for those who maintain the holy scriptures, it poses a number of deeper questions.
If evidence that the divine name was used in the original NT writings grows to become impossible to deny, this should raise deeper questions for both the JW and evangelical view of 'inerrancy' I.e what else in the manuscripts are incorrect, and on what basis can we claim nothing else has been copied incorrectly/changed from the originals. Though, given that the inconsistent JW position should already raise questions for them I don't suppose this will become much of an issue.
Edit: or, I suppose, what JeffT (more succinctly) said