I don't believe this is happening either, but I think some people are making a big mistake in acting like largely symbolic meaning is the same as no meaning at all. I, too, usually refer to it as Disney World (or just Disney) in casual speech, so a name change wouldn't affect me much in a practical way. But it would be extremely telling as to how little respect the current powers-that-be have for the man who is the reason that place and their jobs even exist.
Yes, Disneyland doesn't have the name Walt in it. Congratulations, you're all so clever and funny. But Walt Disney World was named that, by his own brother, to honor him for as long as it existed. If such a name change were to ever happen, it would have to be done with the specific intention to disrespect both men and everyone who loved them. Any other reason ("brand unification", lol) would be a lame non-excuse that only blatant shills would accept.