I want to know how they handle the single person's save data. Do you pack everything into your house and the house is moved to a new island? Does your group progress on the island also come with you or is it like you moved to a new Nook Island and have to unlock everything again? What about your museum donations and nook-azon catalog items?
I'm sure that some people would love to "start fresh" on the island development if they were not the island rep in the past, but others would just want to make a copy of the original island including progress but remove the other players houses (make a copy of the same island).
Will it have its own story setup, like Nook offers to found a new island with you? Whatever it turns out to be, I worry it will be obtuse, annoying for no good reason, and generally disappoint everyone and satisfy no one.