Nomura and Kojima are good friends in real life, so this is not really a surprise.
Well, to all the casual fans who don't pay too much attention to the story and those "I don't play any spin-offs only numbered games count"-whiners, the characters
are still mysterious because most of these people don't know anything about what happens outside KH 1 and 2.
That's more like Nomura's reaction would be if he would
ever frequent a fan forum of any kind. In one interview he specifically spoke about sometimes even changing his own ideas for the plot when he feels the fans could guess too much what will happen.
Considering what some of our best nerds around this forum can come up with in terms of theories, I would guess that
if Nomura would see them he would need to include so many twists and surprises just for the heck of it that it hampers the plot as a whole even more than it already does.
This "tick" of Nomura to have the need to always make the story "surprising" and unpredictable in nearly every aspect is also a factor why it comes over as too complex in some areas.