Current guesses for Disney worlds in KH※
Kumandra
Atlantis
Zootopia
Underland
Tierra de la Muerte
Treasure Planet
Jakku
Yes, I'm guessing they'll be no returning worlds in this edgy elegiac quadratic quest. The best ones to bring back are Halloween Town and Wonderland anyway, and Underland covers both bases in as close a sense as possible. I think Dwarflands and/or the Dominion (or Angelina's Moors) could be in KH4 though. I think they'll save Frozen 2 and Inside Out for KH4 too. And perhaps A Bug's Life, Emperor's New Groove, and Soul, which feel just a bit too cute for Re:Versus.
Treasure Planet is a must. It's been a long time coming, being the accidental sister-film to the first Kingdom Hearts, having the closest aesthetic, sense of adventure, and deeply heartfelt male emotions. ※ is the perfect game for an oddball gem like this too.
You would think Moana, because of the raft adventure parallels with Riku and Sora and she popped up as a medallion in Union Cross too, but I just feel like. Motonui doesn't really offer the highest level of exploration, Caribbean kinda did-that already, and LBR a watercolor Stitch world would be hella cooler if we're going on vacation.
It sounds wild, but this next game is giving me that early 21th century going-for-the-gold slickness and I really think Atlantis would be the cherry on top. I think that's the water world that fits the vibe, with its deep crystal magitek, and I do think the worldlist will be more of a unified vibe this time, like BBS and DDD's were.
Watching it, I felt like Raya was the first movie that was made with KH specifically in mind. And I'm fine with that! Because dragons are simply epic. Kumandra has just the right number of setpieces that legit nothing has to get dropped, you can go straight through the story with Sora, with Riku tagging along with Namaari. And hell yes, they should adapt the movie, it's an original Disney fairy tale. No flimflam sequel sidestory! The statues littering the land are one of the coolest things about the setting, if not the coolest, period. One issue, the music sadly sucked. Why did they go with plain old JNH for the magical Asian-themed movie... Whatever Yoko comes up with will be an undeniable improvement.
It's time for Star Wars, and I think they'll do The Force Awakens, because y'know, it's the Disney one and the most Disneyish of them. It'll have Starkiller base and uh... what planet did Rey and Kylo even fight on? Was it D'qar? For some reason it's very hard to search for. Movie had a homogenized sense of setting weirdly. Nothing quite like Naboo, but what can ya do. Kylo will be a great boss, and a nice parallel to Riku.
Zootopia has such a beautiful color pallette, and I think it would contrast Quadratum really nicely as a drastically different urban world. Furry Riku... I think just the main city setting and the rainforest district are more than enough. Rain effects on furry Riku...
I'm not as crazy about Coco's use of color... I think it all gloshes a bit garishly (especially when compared to the stunning Book of Life, for which it is hard not to) BUT skeletons are always great, and so are those Pokemones, which are very much in lines of what KH is doing with the Spirits. The hypersaturated glow contrasts well with the murky glintiness of Underland, so I don't think those two creepy worlds would step on each other's aesthetic toes. Freaky Mexican heartless and Shimomura mariachi sound excelente a mi.
I feel really strongly about Underland's chances. On a sensory level, it's going for the same thing Nomura is doing with Kingdom Hearts. The script may have been weak (basically trying to be Wizard of Oz/Shrek for no good reason lol), but visually it is a sumptuous garden of dark delights. It's what lies beneath. Jabberwock boss is PERFECT for a series like KH, which is all about the mystery of language and how better to illustrate that than snicker-snackering the wyrm of nonsense itself. AND what a sweet little meta-phor for rebellion, chopping off the head of Thee Great English One (Square-Enix is owned, I'm sure not for the better, by a British holdings company or some other such nastiness). And he was voiced by Ansem the Wise himself Christopher Lee, so there you go, more layers.
I think the original worlds will simply be Quadratum... and the FULL Scala Ad Caelum, baby! Nomura saved us the good stuff for later.
edit: arranged the worlds in the order I think they'd be placed in
edit: I think there will be a new world too. Something technical, not Tron or Game Central Station, but a kind of grander underwiring, something that underpins "reality" or "unreality" something like that. I think the tubes where the past life of Xehanort died are connected.