It's interesting that they are hanging on to quite a bit of Fred Franz's theology here with Revelation & with the end coming in general, while jettisoning a lot of his other stuff, like his subscribing to some dumb Fundamentalist-oddball theory of Hebrew verbs ("proceeded to ask ..."), "torrent valleys," transliterating Sheol/Hades, as well as his complex type-antitype interpretations.
It makes me wonder just what the criteria are and are not. Maybe Jackson just went thru Freddie's NWT and other WTS theological doctrines and decided whether he liked it or not, similar to Splane's comments in an earlier WTS AM, "We like this idea!"
It seems that little to no real research is going on with GJ and his buddies, beyond looking at how "Christendom's" Bible translators rendered the Hebrew and Greek texts and adopting many of their translations. At least Freddie, oddball that he was, did some sort of research.