One thing to add about the "flying Cloud" thing in KH:

After he's done with his little rampage (about 20 seconds worth) he gets extremely tired - to the point where he completely stops for about 5 seconds or so, leaning on his sword, out of breath. At that point, he's easy as heck for Sora to get a few combos on. I'd say that X would take him out right there, if Cloud were to pull his little flying move..