I believe the whole "relationship" between Sora and Kairi thing is just a little silly. I understand where someone might get the idea from, but at the point where KH began it almost seemed like they were too young (assuming that memory serves me correct and that they were somewhere between 8 and 10) to quite get more emotionally complex than BFFs or a summer crush. I also feel that people who spend a portion of their childhood together are less likely to end up together in a lasting relationship due a certain degree of awkwardness, and more likely to have something along the lines of sibling love. This is more of what I feel is going on with Sora and Kairi, and even Riku to a point, although Riku is more a sibling rival for Sora until KH II.
