One of Herbert's themes throughout his works is "women are powerful". You see this in Dune of course, how Reverend Mothers are basically the most gifted people in that universe. You also see it in The White Plague:
At the end of that novel the ratio of women to men is 1 to 10,000, and
women are left pretty much holding the future of humanity in their
hands. They choose multiple husbands, assign whatever importance to
them they wish, and family names become matriarchal rather than
patriarchal as they are now.
So since the main idea in the last 3 books is the Golden Path, which in Heretics is described as:
"They ignore the species at its work, Sheeana. I think you can
already sense this. The Tyrant certainly knew about it. What was
his Golden Path but a vision of sexual forces at work recreating
The entire point of the series is that all of humanity has come to a crisis. Life may end everywhere. Leto figured out a way out of that trap with his Golden Path. And all that is, is humanity going on forever rather than becoming extinct.
The entire series is about this crisis - what leads up to it, how it is solved, and what are the repercussions after. And since sex is how you procreate (if you discount the Tleilaxu, that is) one could make the argument that the entire series is about sex.
So that being said, it would be a typically Herbert thing to do to make the women more powerful, and have women lord the Golden Path over men. Which is exactly what the Honored Matres wind up doing.