His "Golden Path" is very moral, given the goal, and he sticks to that path to save humanity from Spice, and Spice from Humanity. Siona manages to complete the later goal by telepathic rapport with the new breed worm. WHich said new breed is result of Leto II merging with the worms. We see worms being spread. And we see Atreides descendants being immune to prescience. And the new worms, as well...
... Prescience immune worms allows breaking the Arrakis monopoly, a monopoly which the guild wants maintained so that the guild can maintain its monopoly on providing transport. A monopoly that is broken in Sandworms... between no-ships with atreides descendants, and with worms descended from Leto II, and the computed drives in those no-ships...