I think you're panicking prematurely. Even the rumour isn't saying that there will be no help for those with hidden disabilities. Renaming from GAC to
DAS and standardizing how it'll work isn't necessarily a bad thing. Know what to expect is in fact a good thing. Disney is not trying to make it more difficult for those with hidden disabilities. Change isn't always bad.
I don't actually know what even today's GAC can do for the crowds. Crowds between attractions and waiting for shows can't be helped even with today's GACs. If crowds are a problem then using a GAC at a non-optimal time during a busy season like Christmas really won't work for most who need a GAC due to issues with crowds (a good touring plan can really help a LOT with this though).
My 15yo can't handle crowds. We went at Christmas a couple years ago. It was the first time we used a touring plan service. We had an easier time that trip without having to use our GAC very much than we had during trips taken in some of the slowest seasons of the year heavily using a GAC.