The Grid was originally intended to be playable only for Riku, while Sora would visit Space Paranoids. Nomura instead scrapped this idea and had both Sora and Riku visit The Grid.
Originally, elements based on Fantasia 2000 were to be included in Symphony of Sorcery, in which Riku would go to those parts, and Sora in the original Fantasia, however, Nomura found that they "had enough to work with" with the original Fantasia.
Braig: Xemnas and Xehanort made the Organization for a specific reason: round up a bunch of empty husks, hook them up to Kingdom Hearts and fill them all with the exact same heart and mind. Translation: they were going to turn all the members into Xehanort.
1. Kingdom Hearts: Birth by Sleep (Prequel to the original, set 10 years before Kingdom Hearts 1)2. Kingdom Hearts3. Kingdom Hearts: Chain of Memories4. Kingdom Hearts: 358/2 Days (Begins at the finale of Kingdom Hearts 1, runs parallel with Chain of Memories and ends immediately before the beginning of Kingdom Hearts 25. Kingdom Hearts 26. Kingdom Hearts: Coded7. Kingdom Hearts 3D: Dream Drop Distance8. Kingdom Hearts 3 (Whenever it releases of course...)