If the wts changed the 1914 doctrine, they would undoubtedly lose some of their membership, but perhaps not many. Most of them are too brainwashed to question anything that comes from Brooklyn, and a lot probably wouldn't understand the significance anyway. It would be like the "generation" change. I was a little bit shaken by that one, but carried on anyway for another 10 or so years, but a lot didn't bat an eyelid. I doubt if more than 10 - 20% of the congregation I was in then even saw it as much of a change, and hardly any of them, including most of the elders, attached too much significance to it.
To change the 1914 doctrine would probably create more of a stir, but the majority would most likely stay in the spiritual comfort zone they have built for themselves and carry on regardless. They would probably be relieved in some way, it would be one less thing for people to challenge them over, and the majority of jws I have known don't like challenges to their beliefs, especially on matters like 1914 where there is doubt over the dating method they used to arrive at it.
I wouldn't be at all surprised if the gb did change the chronology, but if they did I'd expect them to do it gradually, to dampen down the significance of what was happening.
just my two penneth