Having read both of Ray Franz' books and more recently 'The Gentile Times Reconsidered' by C. O Jonsson you'd be forgiven for believing that losing the 607 B.C.E date for the destruction of Jerusalem would end in disaster for the Society. Sorry but I just don't think so.
I'm sure many of the long-time Witnesses who know the history of the Society would truly have problems but most of the dubs just don't care! Think about it, remember all those dubs you used to hang out with. When did you ever discuss Russell, Rutherford or the choronology of the neo Babylonian period. Nah! You just went to the meetings, did your bit of field service and then made plans for the weekend or the next party (get-together).
The Society could adopt the 587/6 date and 95% of the dubs would not even think twice about it. There might be some questions floating around, some undoubtedly would leave while others would remain and 'ripple the waters' for a while but in the end everyone would just end up back in their cult-induced stupor.
The key is this - who gets there first. If the Society tackle the 607 - 587 issue first then they are in control and can spin it any way they like ( remember 1874, 1914 1925 and "the generation"). They will win because they are perceived to be teaching with authority. However, on a one-to-one basis, exposing fallacies like 607 can still work because it helps to break that very same authority!
The moral of the story? Act now!