A thought: If one issue gets worldly people incredibly stirred up against Witnesses, and the public starts telling Witnesses that they are being lied to by their leaders, and then a few of the leaders just can't take it anymore...
It is possible that the beginning of the end may look very much like them being publicly caught "red" handed. To tell the truth, the child abuse scandals, the UN/DPI Association, and the lies about 607 BC have probably all created an environment where this kind of thing would be possible. Now, all that is left is an issue we can get behind exposing that will have some legal force backing it.
Once we have that, we can batter down doors to bigger things. Barb didn't say this would be the biggest thing possible, she just said it was bigger than the things that have come before. Every increase in magnitude adds weight to our arguments and tips the scales in our favor. We are painted as the deceivers, but we are the ones trying to uncover the truth. The media will know how the land lays and our word will carry further, as long as we speak responsibly.
The key to me is that, whatever this is, Barbara said the public will care. In my opinion, people are jaded about the money scandals that have been going on. But they are due for some other kind of scandal to get worked up over. The thing is, this stand on blood is fairly well known by the public already, and the Witnesses are largely despised for it. If it is the blood issue, and if we can get national attention attracted, who knows how many other opportunities it will open for us to be made aware of dark secrets?
The money thing would require Federal investigations before anything could be done, unless it is some sort of class action lawsuit (but that would ordinarily have a lot of precursors, too). This has the feel of something private sector, but at the professional level. Blood issue fits that bill, too.