It's fucking amazing news to see Toy Story in there... not only one of the best things Disney owns, but shows that they're using some of the new shit they've bought since KH2 came out. Bring on some Monsters Inc/Incredibles based levels now!
Saying that, if they're actually going to use Marvel, you could probably skip the incredible... if not though, get on it!
Of new worlds, I hope they only stick to Pixar stuff, which is already quite a push but at least still broadly conforms to Disney themes. Marvel universe stuff would break the aesthetic unity of the series; it is fantastical in content but not in style and spirit, imo. I also don't want to play any Kingdom Hearts game that has a recognisable New York world, because this series is silly, sincere, soppy, wacky but also fundamentally colourful and unreal, and it should stay that way.
Yeah, to be fair one of the weakest parts of all of KH is probably the POTC level, and the real world setting did feel a bit off. If they were to do Marvel, I'd probably rather see them go with something more out there/not set in New York... fuck off to Asgard, or pull some Doctor Strange shit. That should still work I reckon.
On this topic, what do we consider to be the best KH levels? I just remembered that fucking amazing retro black and white part of KHII. That's possibly the best for me.