Olympus Coliseum (Hercules)- Ok, I'm bias, Hercules is my favorite, but it wasn't in 3D, so it needs to be in KH3, would love to see some more story driven stuff like we saw in KH2, along with the traditional coliseum matches.
Hawaiian Paradise (Lilo & Stitch)- A continuation of "Deep Space" from BBS, basically the main plot for Lilo & Stitch.
Arendelle (Frozen)- This is practically a shoo in, with it's global success (especially in American & Japan), Marshmallow could make for a great corrupted boss taken over by a heartless/nobody/unversed.
Metroville (The Incredibles)- This is my favorites Pixar movie, and with all of the costume changes and transformations Sora, Donald & Goofy have had over the years, I want them to get cheesy superhero outfits in an Incredibles world, with cheesy names they give themselves like Key-Boy, Magic Quack & Shieldman, lol. Not sure where in the timeline this could take place, honestly a good time would be in the prologue before Mr. Incredible & Elastigirl were married, but then they'd run into issues with the Elastigirl name, so that's unlikely. It would probably be mid plot against Syndrome, or post plot against a new villain.
Game Central Station (Wreck-It Ralph)- Ok, so I want this to not be a traditional world, I actually want GCS to be the new Hundred Acre Wood of KH3, a world that is actually a collection of mini games. Maybe Merlin rescued these three game cabinets and plugged them into the TRON terminal or something along those lines and Sora has to fix the data among the three arcade machines, etc... by playing the mini games of racing, FPS & platformer (or something of that sort).
Louisiana Bayou (The Princess & the Frog)- I want this to happen, I completely loved this movie, although nostalgia goggles may have had a tiny bit of an influence because of the 2D animation, but still. It was a great movie with an excellent villain (KEITH DAVID!!!). I want more animal transformations and I could see the gang turning into bayou animals, Sora into a frog, Donald into a bayou native bird and Goofy into a red-eared slider turtle (not a sea turtle or tortoise).
Andy's Room (Toy Story)- I want a Toy Story world, and since KH3 will not be the end, we should start at the beginning of TS, Heartless would fit in perfectly with Sid's toys and I want to see TS in KH! Sora could be either an action figure or wind up toy, Donald a rubber duck or one of those wooden ducky pull toys & Goofy either a ragdoll or marionette.
Pridelands (The Lion King 2)- YES! I KNOW! TLK2 was a dtv sequel, but guess what? So was Return of Jafar, and that was in KH2. Kiara was teased at the end of KH2 and TLK2 was a quality sequel imo, ntm I would love to see a return of lion Sora!
San Fransokyo (Big Hero 6)- This wouldn't be a transformation world like The Incredibles, Sora, Donald & Goofy could stay themselves, but they'd have to help save the city, I look forward to seeing the movie in November and expanding on this idea then!