Possible new light on 70 years
I may be reading more into this than is there, but here is what I've spotted from today's watchtower study (Oct 2016 study edition) page 14 paragraph 8. Concerning Daniel it says "Thus, some 70 years after his arrival in Babylon, he was still known by his Hebrew name" referring to an event in the first year of Darius ie 539/538 BCE. However, according to the WTBTS chronology Daniel went to Babylon in 617 BCE - more like 80 years earlier. Could this (finally) be a step towards ditching 607?
In the original writings the year was 606 BCE based on the capture of the king of Jerusalem. I don't know when they changed it to the destruction of Jerusalem. Anyway pretty soon they'll have to move the whole thing forward like they did with the rulership of Jesus.
If they just did the same doctrine but moved it up 20 years -- 587 BCE to 1934 CE and ditch 1914 -- that would have at least spared them the overlapping generations nonsense.
But, eh. Too much egg on the face.
Probably just someone made a mistake. If they were going to drop 1914 this would be a pretty strange way of introducing it.
The book called Daniel is a historical fictional novel written in the middle of the second century BCE. Being written in the first person, it convinces the gullible that Daniel was both real and contemporary to the events described. The text takes a spin on events which had already happened hundreds of years before as imagined in Babylon but referred in part to the prevailing Persian politics. The surest way to write prophecy is after the event!
The JW organisation as 'God's only channel' has had nothing on which to claim divine attention except to predict 1914. It never did foretell WW1 but the year when paradise would arrive, so it is a dishonest boast anyway.
To expose the faulty basis for 1914 in the Watchtower would remove the only vestige of god-magic it can muster.
I get the impression that for very many years, among the upper echelons, belief in 1914 whether true or not, is a sort of in-house code for fidelity to the GB, it almost seems masonic.
537 to 607 is still 70 years in their doctrine.
Could this (finally) be a step towards ditching 607?
Who knows? Who cares? If it's already established that they say one thing and later say another, why continuing entertaining their nonsense?
607 BCE as the date for the destruction of Jerusalem was thoroughly discredited to the WT in the 1960's by letters sent by the eventual writer of "The Gentile Times Revisited", from memory his name is Carl Olaf Jonnson (spelling?).
So they have stuck to their historically inaccurate nonsense for half a century, they are not going to rock the boat now.
They have buried the actual basics of the doctrine so that the vast majority of JW's today know nothing about 2500 years from 607 to 1914.
Today's JW's just take it as a given that 1914 saw Jesus stuck on a Throne in 1914, and told not to get off till he had done his business, but JW's don't know why, and they don't care.
They can't drop 1914. because that could also affect gravity, electricity and wind :)
Every factual statement made by the W.T ends up requiring reading more in to it than the original interpretation. As for your O.P " possible new light on 70 years" I would say highly probable. Why waste our time with these manipulators, when we know they know it's bullshit....just walk away.