Author's Saving Throw: One of the biggest complaints fans have had since the second game is that the Disney worlds have largely been relegated to watered down retellings of their source material and proving to be tangential to the main plot of the series. III firmly reverses this trend, as all worlds announced so far have stronger ties to the main plot and are not retellings of their respective movies.
Mandy Moore was part of the celebrity cast in the first game, providing the voice of Aerith. Fast forward to more than a decade later and with the inclusion of Tangled among the Disney worlds, we have a starring character voiced by her. Time will tell if Mandy Moore will return to the franchise to voice Rapunzel.
Ever since Disney purchased Marvel, and when this game was first announced it was exposed that one of the worlds explored would be Big Hero 6 (which is a Marvel property, even if highly modified), people have been clamoring like crazy to have more elements of the Marvel Universe appear (even as "secret bosses"). Now, it's been announced that Square Enix and Marvel have negotiated to make games together.
This meme is now very ironic since the D23 trailer that confirmed a world based on Toy Story world would also reveal the game's release window of 2018.
"Holy Shit!" Quotient: From D23 2017: The release window was finally announced to be 2018, and with that confirmation also came the news that Toy Story is the first Pixar world to become part of the series.
Internet Backdraft: The game has been anticipated since the release of Kingdom Hearts II in 2005, which has left a lot of people jaded and antsy about the game being released in a timely manner (or at all), with comparisons to Final Fantasy XV (which took a very long time to be released after its announcement). Even with the announcement of a 2018 release date, people are still joking that the game will be delayed.
Misblamed: The recent rumor of the game not seeing a release till 2020 stems from a misunderstanding of what was actually said. Square Enix gave the release window of this game (and several others) as being within the next three years and news articles jumped on it, claiming the game (along with Final Fantasy VII Remake) had been delayed.
Tear Jerker: The Big Hero 6 world will take place after the events of the movie, where the Heartless will possess the Baymax that was left behind inside the portal near the end of that film. What the hell, Square?!
Uncanny Valley: Likely because the game is in development, but the first full E3 trailer had some awkward looking facial designs.
The Jump Festa trailer is pretty much winning over a lot of people in the gameplay department. Flowmotion, Shotlocks, and the Classic Combat System all in one package? Hell. Yes.
With Olympus Coliseum being in almost every KH game (Dream Drop Distance is the only exception), many fans were VERY happy to see that the Hercules world of this game will feature all of Mount Olympus and not just the Coliseum.
Many of the worlds shown so far have exceptional detail in 3D. This is shown especially well in Hercules' world, which was originally a 2D film.
The in-game graphics of Toy Story's world are almost indistinguishable from the movies. They even nailed the design of Andy's room and the entire neighborhood block! To really hammer the point, even Pixar staff members were shocked at how great the graphics looked!