And again, he defeats Heartless with it and hearts are released, which only Keyblades can do, so it IS a Keyblade.
Wrong. Any weapon releases hearts from Emblem Heartless.
Only the keyblade does so permanently
For other weapons, the hearts just float off and become Heartless again:
Marluxia: The rest of us can defeat Heartless, but we have no way of
collecting the hearts they release. Eventually, the hearts will turn right
back into Heartless. You see, then, how special you are?
Nomura has already said the Soul Eater is an intermediary for the keyblade, as others have already pointed out, ie not a keyblade.
Illusions would make the plot irrelevant and would waste the time of the gamer.
No more than the data in coded. Essentially the same thing, really.
Time travel is a route nobody wants KH to take.
Which would never stop them from doing it considering they do things all the time that fans don't like.
There is an importance in Dreams obviously so why not make it a dream in reality? Like how Tidus is a dream existing in reality.
This isn't a bad idea.
I'd be pretty upset if it turned out that 3D is entirely dream based, because that would mean that worlds like Notre Dame don't really exist.