The issue I see and why Haven & Yacht club are successful, you need everything exclusive behind the magic doors, cabins, restaurants, lounge, bar, deck...... you don't have to go far to get access to everything, restaurants are steps away from your exclusive lounge and bar..
RCI and Celebrity tried to patch up older designs to provide the facilities to try to compete and it took time
Why Princess did not take the opportunity to go ship in a ship with a brand new ship is surprising, MSC and NCL are on multiple iterations of the concept while princess is patching up old designs to try to get more exclusive(more $) like others did years ago, what we have is a private sun deck with a lot of suites below it.