MOBA with systems inspired by the mainline KH games. Teams of five travel down each lane to destroy the cornerstones of the other team. Light team tries to lock the keyhole on the dark team's side. Dark team tries to open the keyhole on the light team's side.
All that established, there would be no restrictions on what characters could wind up on either side. The only aesthetic difference in teams is that all dark side characters have the yellow eyes, and light side characters don't.
Each character gains AP as they level up, allowing them to select permanent abilities. Certain characters are aggressive lane attackers, like Sora and Saix, while others play defensive support, like Goofy and Ansem. Other characters are better at poking with magic and taking out AI mobs, like Aqua, Donald, and Zexion.
It'd play like a faster Dota 2.