DQ as a whole is a really fun and (most of the time) light-hearted series of games, at least when compared to Final Fantasy's more gritty and serious stories. I definitely wouldn't mind seeing it in KH, would mix very well with Disney's overall tone. 3, 7 and 8 I think have the most fitting characters.
The big issues here, I think, are its artstyle (same issue as with getting Chrono Trigger in KH, Akira Toriyama doesn't mesh well with everything), the fact that its many and varied monsters play a very important role in the series which would be hard to translate into KH (you CANNOT have anything DQ without at least slimes and drackies, though I guess FF in KH has made it this far without chocobos so who knows), and the fact that Nomura might pull the good ol' "I don't feel comfortable working with characters I didn't design" rhetoric that he used back before he worked on Dissidia.
I'd kill to see Alena or Yangus in KH, really.