This first quote establishes that the Tleilaxu are interested in researching not only technology but also various methods of control, legal or forbidden.DM wrote:"You believed the silly Emperor was the prize we sought," Bijaz said. "How
little you understand our masters, the Tleilaxu. The Guild and Bene Gesserit
believe we produce artifacts. In reality, we produce tools and services.
Anything can be a tool -- poverty, war. War is useful because it is effective in
so many areas. It stimulates the metabolism. It enforces government. It diffuses
genetic strains. It possesses a vitality such as nothing else in the universe.
Only those who recognize the value of war and exercise it have any degree of
self-determination."
Here we see that the Tleilaxu have a department of religious engineering, reminiscent of themes in The Dragon in the Sea. Bijaz seems to be indicating that Muad'Dib taught them something new, pertaining to the merging of religion with government.DM wrote:"And if you're not yet close enough to strike, speak of how much the
Tleilaxu admire what he has taught them about the possibilities of religion.
Tell him the Tleilaxu have a department of religious engineering, shaping
religions to particular needs."
Fast forward a little to GEoD and further, and by now we've read on a few occasions that the Tleilaxu have a sort of strange reverence for Muad'Dib, and even for Leto II. This is not explained when it's brought up, and seems like it implies more than merely admiring how powerful they were as rulers.
Now finally we get to Heretics and CH:D, where we learn for the first time that Tleilaxu society is a complete theocracy, with the religion so pervasive that even the Tleilaxu Masters are restrained by its tenets. And now we're set to put the pieces together. It appears that in Muad'Dib's time the Tleilaxu decided to implement a religious government on their world for the first time for the purposes of control. By the time of Heretics this religion had gone far past the point of merely being the trappings of religion to manipulate the people, but had become a real religion where everyone believed it. It's no wonder they would revere Muad'Dib, since they would probably have credited him for founding their religion, in a sense.
By Muad'Dib's time the BG were already aware of the possibility of merging the state with a religion, and they knew how dangerous it was. Jessica relates this fact to Alia in CoD, telling her how dangerous it is to balance statecraft and religion. Perhaps the BG at one point experienced the problem of adopting the trappings of religion; it has the danger of becoming a true religion as it did for the Tleilaxu, and taking hold of the people who thought they controlled it.
The question remains, what kind of society did the Tleilaxu have at the time of Muad'Dib and before? We aren't told, but based on Bijaz's comments it seems they were a secretive research-based society, probably secular, and very interested in the idea of power. Sounds sort of like us right now, no? But we are very subtly told the danger of their methods; the methods took them over and by the time of Heretics they had become a strange people on an extremist religious mission.
The cool thing about this turn of events in the books is that we can't actually understand it without reading the final books and then going back to re-read the earlier ones. Bijaz's comments are not that noteworthy on a first read, but after having read the last three books take on a whole new meaning.