Reading through it I got to this:
Herbert borrowed several other riffs from Sophocles, including the blind prophet, the hero becoming blind at the death of his wife, and the flawed person being sent out into the wasteland to die (rather than burdening his family and tribe). Herbert also flirted with the subtheme of incest: if love can only exist between equals, there aren't enough superhumans on Arrakis to go around, so Atreides siblings tend to fall in love: Leto II and Ghani follow the Path of Light, refusing to act on their almost romantic love for each other. Alia is in love with Paul, so she arranges for him to chance upon her when she has no clothes on. This attempt to seduce Paul into an incestuous relationship is evidence that Alia has fallen to the Dark Path.
Interesting take on the Alia fighting naked thing. That's not what I thought it was about. I took it to be her need for a mate; basically what Stilgar points out. Mohiam tries to see if incest is possible but both Paul and Alia seem to object to the idea.
While Leto and Ghani share quite a strong bond Leto says:
Sister mine, I love you more dearly than myself, but that [Ghani bearing his children] is not the tender of my desires.
Before this, however, Leto does was "suppressing the inner betrayals". Which might suggest he speaks other than he thinks. But I think this is a possible reference to his taking the throne but marrying Ghani in order to retain the Atreides name.
Anyway, any thoughts on either pairing?
(By the way, sorry if this is an awkward subject for anyone.)