Instead of Christopher Robin I always figured Merlin would just give the book to Sora for keeps.^ Same. I don't think I'll ever get tired of 100 Acre Wood, so I'm glad it's coming back for the wrap-up of this saga. I've always been fond of the fan theory that KH3 will show Sora passing the Pooh Book along to Christopher Robin (somehow), that would be great closure for this world. Plus, I think a lot of the inherent value of KH3 is not just seeing what new worlds are included, but how old worlds, environments and concepts are updated to take advantage of the new engine, so the more of that the better.
We are getting more new worlds though. Nomura already stated most of KH3's disney world's would be newI totally agree with you, I'm very surprised that people don't want more new worlds.