While I would love for full gameplay featuring disabilities in the future (and agree with things stated above - that putting it behind a pay wall would be bad, and that making it "curable" would be bad, but it should also be optional for a variety of reasons) I would actually be okay if, at least for the time being, they did just release some deco/cosmetic stuff that doesn't impact gameplay. It could be a sort of stop-gap or similar.
Obviously full gameplay would need to be more in-depth. But if, for now, they were to release some "prosthetics" skins with options for prosthetic arms and legs, some eyepatches, options for "glass" eye recolors that are a little shinier and don't move as much (and don't have to match the corresponding eye, though my best friends' eyes also just naturally don't match, so maybe that should be an option anyway), and hearing aids for sims to wear. I realize it'd be disappointing that it wasn't a complete experience and instead just a cosmetic difference, but I do still feel like it would be a welcome addition. Especially as it would be a lot less work than all the new interactions and animations needed to make even just physical disabilities (disregarding mental disabilities, which would be more complicated still) part of gameplay.
I'd love a full experience, for sure. But I wouldn't say no to the deco objects and accessories being available even if they couldn't add gameplay right away.