Did you know Nihilus had dreadlocks under his hood? It's on the Hasbro Sith Evolutions Set:
The KotOR Campaign Guide states that he had become a shell devoid of flesh and that mask, robe, and lightsaber were kept together with the Force just to give him a form. This is a piece of promo art for TSL showing a clearly flesh and blood arm:
Then there is this ongoing comic series based on KotOR. Zayne Carrick, the protagonist, is thought by many to be Nihilus' former self.
I personally liked the idea of Zayne becoming Nihilus, but I don't picture him wearing dreadlocks. Throw in this empty shell bull**** and it feels like nothing makes sense no more. I would ask Avellone if I weren't sure he's not making comments on this sort of thing, or JJ Miller, the guy who's writing the comics.