I just finished The Name of the Rose by Umberto Eco, and I was fascinated by the zeal and even violence by which the various factions and orders within the Catholic Church disagreed on matter of theological doctrine.
In the book, there is a gathering between Fransescans and the Pope's envoys, discussing a disagreement of doctrine about whether or not Christ was poor. This would somehow determine the right of the church to meddle in secular matters, and as such was an important topic both to Pope and Emperor.
The debate descends into a regular fistfight, with the robed monks of several monastic orders insulting and kicking each other in a general melee and mayhem, and together with the tales of prosecution of large cults/factions for Heresy, people burnt on the stakes for refusing to accept that Jesus did not preach poverty left me quite amazed.
Now, I figured it would be amusing to make something like this the setting of a DH adventure, travel to some shrine-world to observe/participate/investigate a delegation in such a debate about doctrine. A debate about some insignificant aspect of a minor saints life or teachings, that descends into open warfare between orders within the Imperial Cult.
However, to which degree is anything up for debate within the Imperial Cult? Even if this debate was restricted to the ordained ministers of the cult itself? I know new saints are added all the time, so obviously the cult is alive and no static, finished thing.