I can only see this being applied to a new EP if its about disabilities. But this will probably not happen because disability rep shouldn't be commercialized.
But if they ever do an update for disabilities GAMEPLAY (we have some items but not gameplay), which i wish they do, they could just add this to Cats and Dogs EP. It's not like they need to do a whole pack refresh. Sometimes they update things from older packs like the clubs activities with new packs.
I remember they were going to add cats and dogs at weddings but they discarded it. I wonder why. Was it because of features limitations per pack? Lack of money? Low time until launch? I don't know but they were very close.