Ah, but Ansem isn't a Heartless... He is a heart!
I still stay by my theory. My age doesn't prove I cannot understand the philosophical stand points of the game. Also, what the novel states can only be precieved as half-true to the Kingdom Hearts line. The novel have stated that Nobodies have emotions, yet still lack a heart and thus still feel empty inside. I'm sticking to what the game has stated a million times: Nobodies don't have hearts and don't have emotions. Also, did the novel say that Xemnas was stronger than Ansem before or after he absorbed the KH moon's power?
And before when everyone is like "but when Sora was weaker", Sora beat Ansem because Sora's the hero. He has to win. Or else the game would suck because it would end with you getting instantly killed in the beginning of Destiny Island when the Shadows appeared. Besides, Sora didn't technically kill Ansem. Ansem was destroyed by the light within Kingdom Hearts.
Unless you bring me an interview where Nomura said point blank, "Xemnas rawks, Ansem suxs', then I'm standing by my point. Also for a nobody to be created, it takes an extremely strong will to live and the heart must have been strong as well. This circumstances give Nobodies a seemingly leverage over Heartless, but Heartless could be created from the Darkness emitted from hearts alone. Heartless gather strength in large mixed numbers, Nobodies usually have small groups. There are some pretty strong Heartless as well, remember Darkside?