Kingdom Hearts 4: 12 Disney & Pixar Worlds We Want To See
11. Inside Out
Easily one of the most endearing qualities of Kingdom Hearts comes wearing its heart on its sleeve. Sure, it's easy to make fun of for that, but that earnestness of emotion - even if it may often be over the top - is such an intrinsic part of the series' DNA, it exemplifies why fans love it so much.
As such, including Inside Out seems like a no-brainer. And as we saw in the film, everyone has their own Headquarters populated by personified emotions, meaning that a visit into a Kingdom Hearts' character's own head would result in meeting familiar faces like Joy, Sadness, Anger, Fear and Disgust.
Plot-wise, all it would take would be some dastardly evildoer infiltrating, say, Sora's mind in an attempt to destroy his happy core memories in order to justify a trip inside.
The emotions could help out along the way, and Sora being driven by his attempt to hold on to all the memories he's come to keep close about his friends would fit right in with some of Kingdom Hearts' most prominent themes.