I think a huge change in literature, e.g. combining the WT and Asleep! into a JW.org magazine would be significant. . .
this has been my speculation. A complete rebranding of the WTS. Watchower only existing as the study edition so they can say its been continuous since 1874 or whatever. Other than that, JW(.org) Magazine. The WTS will be renamed with JW something or other
but I don't see this being "faith testing". The mags have been revamped as if to prepare for this change already without a blink and the R&F are eating up the JW.org bit.
lets think about it, we have all discussed ad nauseum what the BOrg could do to cause a mass exodus and we can't really come up with anything short of major criminal charges
the only doctrinal changes that could really test the faith of the R&F is a major shift in the 1914 teaching (perhaps tied with a 607 change).
they would never make a big pomp about blood with a zone visit, they would phase this in over decades. Anything other big change wouldn't be that big. What else could they change that hasn't been already?