ok let give my point of view on u're theory....
this is what i think...there's only one keyblade master peroid, and yes perhaps there's other keyblade wielders. Why would u need 3/4 keyblade masters, it takes 2 to seal kh and one 2 seal the keyholes in each world. And maybe u're right about the sora-light...etc., but what about riku. And even so, there's a world of light, sora is not necessarily light since he was never born/or set foot on this world, same goes for king mickey(but not sure), as for bhk i agree since he's originally from twilight. I also think there're just worlds that sora has to travel to in order to seal them (i don't think there of great importance to the game)...that's what i think, u can give u're point of view on my answer.
