My two cents on possible future new light, when Armageddon obviously failed to materialize within the overlapping generation:
In Mat. 24 Jesus first mentions 'this generation'. He continues to say that those days will be like the days of Noah.
The myth of Noah claims Noah was 600 years old when the Flood came. Or in other words, 'the days of Noah' - Noah's generation - were about 600 years long.
Clearly Jesus referred to Noah's 600 year long days to indicate that 'this generation' could last a couple of hundred years. Still within a single 'day' for Jehovah, right?
Now I think my idea makes a lot more sense than the current convoluted Splanation. I don't believe either one though :-D
New light like that would buy the GB quite some time. 2514 here we come!