Available, you asked, "What changes in doctrine (if any) do you think have come as a direct or indirect result of Ray's and other's books?"
Ray made mention, long before the change in the generation explanation, that they (the GB) would have to come up with something, as all of the GB would be dead before long and then what. Hence, their understanding of the generation of 1914 changed, newer and younger members of the GB were added.
There are probably more, but I will leave that to some of our more enlightened ones on this board.
"By doubting we come at truth" -Cicero