khiethy:

Before speaking with the staff, Nomura had chosen over 20 worlds to include in Kingdom Hearts, including original worlds.

To whittle them down, worlds were chosen based on popularity, if there were interesting characters to play as, and if there were interesting places to be in, in that order.

Source: Kingdom Hearts Ultimania

Nomura was like a kid in a candy shop, wasn’t he? I know I’d try and put as many worlds into Kingdom Hearts as possible! Would you have done the same? Come tell us on the forums, and discuss all of the past trivia with everybody!

(Source: khinsider.com)