Just remembered something I was going to include earlier, on the topic of the generation stuff. For one thing, I do remember even in my childhood the 2034 date being suggested (but, of course, the end couldn't possibly be that far off) based on the parallel with noah. I would not be in the least surprised if they started subtly pushing 2034 as the date of the end in about 10-12 years. This seems especially likely, since by that time the GB will probably be made up of several that weren't around (or aware) in 1975, so the lessons of the past outcomes of date setting will be mostly forgotten.
As for the change from the 1995 and 2008 'generation' teachings, I'd guess that it was a (failed) attempt to reenergize the R/F. based on the 1995 and 2008 versions, the end could potentially be another thousands of years off (especially with the 2008 flavor, since in that version the "generation" was already nearly 2000 years old). There's only two explanations for the change. Either they're intentionally trying to see what they can get away with (or as has been suggested here, trying to get rid of fence-sitters) or they're trying to recapture the urgency that the organization had pre 1995.