I would be surprised if there was any significant change whatsoever.
Remember the "biggest" changes happen little by little over longish periods of time. For example, there is a huge difference in manner and behaviour between the JWs of the 1930s and the JWs of this century. My grandparents who converted to the Bible Students in the 1920s would be absolutely shocked by the relatively "easy-going" nature of modern JWs and view them as apathetic and nominal in the faith. There was a hard-edged driven quality to earlier generations of JWs: they deprived themselves of so much in order to dedicate themselves to "Jehovah" (i.e., the organization). The ongoing subtle tinkering of the 1914 doctrine is a case in point: No, they did not come roight out and do and overt about turn on this central doctrine - they drip fed changes that escaped most members attention - but the changes were significant. My grandparents went to their graves earnestly and adamantly believing that the generation that witnessed the commencement of world war one would still be alive here on earth when Armageddon strikes. It was never open to question; it was an incontrovertible fact. Also, there were hard and fast rules about so many things to do with personal choice issues that nowadays the JWs are relatively more relaxed on. In the 60s I was visited by the presiding overseer because the shirt I had worn to the meeting was considered too colourful and I was accused of drawing attention to myself. I was told to wear only white shirts or pastel colours! Look no further than younger JWs and I swear that in many respects they are no different than members of other bland religious groups like the Mormons and 7th Day Adventists.