Other than the fact that they dual wield glaives - which to my mind, being swords, has as much to do with Rogues as it would with Warriors, or any sword using class, as 2 out of 3 Rogue specs do not use swords.
It's bothering me lately because 4th spec has been a popular topic of discussion and Demon Hunter keeps coming up as a 4th spec for Rogues, which I not only don't want, I just don't see how it makes sense. Rogues are, you know, thieves and assassins and stuff, not magic adepts that can metamorphose into their inner demons - right?