I've been thinking lately... about how Terra could still have influence through Xemnas... about how Nomura might pull a fast one on us in the end...
The Xehanortification process seems to have an interesting result: loyalty from whoever is affected. Xigbar and Saix were arguably some of the most devoted members to the Organization.
Now, why would Xemnas want all those members of the Organization under his control? He didn't seem disappointed when Saix and Xigbar, two of his Xehanort seeds, were killed by Sora. So what was the point of bringing the entire Organization under control.
The true goal of Xehanortification, for Xemnas at least...
Is genocide. The human-like Nobodies represent some of the most powerful beings in the universe. Xemnas wants to be on top, he wants to ensure that nobody would have enough power to rise against him. And then there's this quote:
In my opinion, Xemnas just wanted to ensure he had full control over the universe. With one last detail...
Aqua and Ven. Everyone knows Xemnas was obsessed with finding Ven in Castle Oblivion, but wouldn't there have been easier ways? Xemnas could have easily transformed his appearance to mirror Terra's and searched for Aqua in the Realm of Darkness (she has no black coat, so he could find her scent). Then he could have convinced her to bring him to Ven at Castle Oblivion.
As far as we know though... that didn't happen... or if it did and he failed, she would have looked ANGRY upon seeing the hooded Ansem the Wise in the secret ending of BBS FM.
So why was he always sending the Organization after Ven? It wasn't to find Ven... it was to ensure he COUDN'T BE FOUND! He wanted to test the security of Castle Oblivion, because he was planning on inducing a mass genocide in the Realm of Light.
I believe THAT is the empire he intended to create, one in which solely he, Ven and Aqua existed.
And if you ask me, I'm not sure if that goal ever went away. A Keyblade War would more or less accomplish the same, no?