It's my opinion that Leto II didn't see much past the events in Heretics. His whole idea was to free humanity, make sure all the eggs weren't in the same basket. To do so, he helped create Siona and her abilities (basically a no-person). I doubt he forsaw the Ones With Many Faces forcing the HM's back into the Old Imperium, he was more worried about machines hunting down humans, something he most definetely prevented. He couldn't see past things in Heretics because of all the "no-people" running around. Things progressed past his line of vision...and that was his plan. Taraza, Odrade, and eventually Teg, all saw it didn't work quite well enough: they destroyed Dune (or maybe it was part of Leto's grand scheme to have the destroy it, either way). It's kind of a pointless argument, though. I could say he didn't forsee the danger of the Ones With Many Faces, and Sheena will somehow have to forge a new plan to defeat them (in 7). Someone else could say, "Well it was Leto's plan to have her do something." And it can't be proven either way. Without what Leto wrote at Sietch Tabr, I would say he didn't know that the BG would have to augment his plan by destroying Rakis. But taking into account what he said....well maybe he knew Taraza had died, that Odrade would go ahead with her plan....but he couldn't have known what Teg would do, he had the mark of Siona, and abilities beyond the God Emperor, in some respects. Who knows?
