Alright, well while reading a post, I was developing something in my head as most people do. At the end when Sora said that he knew then that Kingdom Hearts, the otherside, was light, and at the time he was clearly in the darkness fighting Ansem. When Mickey was looking for the other keyblade on the other side, he was looking on the otherside of Kingdom Hearts, the light side while Sora was looking on the side that we played as. Well, seeing as how Mickey found the Kingdom Key on the light side then wouldn't that mean that Sora found the one on the dark side. It'd be like ying and yang, the light keyblade on the dark side and the dark key being on the light side. Sora could have the light or the dark keyblade. I was thinking that might explain the darker look in his new outfit. And when the voice near the end when Sora, Goofy, and Donald are chasing Pluto says that Sora will be the one to open the door to light, maybe he would be using a darker keyblade than the one that Mickey had found to open the door to light.