It will be interesting to see whether the now in-process agenda will indeed move beyond FS time reporting and dress & grooming into doctrine. When the 2013 rev. NWT came out, there was plenty of hidden rejection of FF's ideas scattered throughout the revision, so in some sense, doctrinal change had already begun a decade plus ago.
Most R&F Witnesses could care less about doctrine and any kind of "in-depth Bible study" especially about prophecy. That's what the 607/1914 Gentiles Times madness is all about. So if the current GB changes that, I suspect there would be little negative reaction from the R&F. In fact, there might very well be relief: "Thank God I don't have to attempt to teach that anymore!"
There would probably be serious opposition to the idea from spacy Splane who still seems enamored by prophecy (evidently the only one on the GB still caught up in that), but with the rest for a change on 607 etc, and doofus Splane witnessing what happened to his erstwhile buddy Tony Morris who stood up against the majority will, he's likely had the fear of Jehovah put into him against fighting what the bulk of the GB want as their agenda.
I repeat, it will be interesting to watch what develops here.