Lets clear out a small misunderstanding.
So the Brass God would be used as a divine skin and the souls of the Dwemer would be used to create it. - Lugar
The Dwemer did not become the skin of the Brass God. They became the Anumidium which can be used as a Divine Skin. People seem to have been misreading this.
This is in line with what Xal says:
The Brass God is Anumidum, the Prime Gestalt. He is also called the divine skin. He was meant to be used many times by our kind to transcend the Gray Maybe. - Xal
The Brass God is called the Divine Skin.
He would not have sacrificed so many of their golden souls to create Anumidum's metal body if it were all in the name of grand theater. - Xal
And the Dwemer Souls were used to construct the Brass God.