I am going for several things with Copernican Sovereignty both in the setting and with the rules.
The setting is not supposed to be gonzo in the genre-bending sense, but it does shift aesthetic and technological registers dramatically between campaign regions. The lowlands controlled by the Copernican Elect serves as a kind of metropole in contrast to the adventurous hinterlands. The style of these two areas is thus intended to be different. I see the Elect with a vaguely Napoleonic or even Axis styled militaristic demeanor, though not mapped to any particular Earth culture. The more extravagant Elect may present themselves in a fantastic and less conventional manner. Ideologically, they are half scheming Roman patricians building family dynasties and half messianic modernists. They have managed to subdue the gods and harness their power for mortal benefit and certainly this is Progress with a capital P. Many “monsters” in the lowlands are creations shaped from god-matter or artifacts powered by god energy, such as the multi-hued Dractonothopter airships or the giant Panzer armor suits piloted by Copernican Knights.
The simultaneous existence of different levels of development, with adventurers coming from the wild side, is something that deserves a separate post. I want to emphasize that the Elect are not supposed to serve as an evil empire. Though particular members of the Copernican Elect may be adversaries, I could just as easily see them as allies or patrons to adventurers.
In terms of game details, though I have been using some monster books, I do not plan to use any modules. This is approximately the inverse of my last few campaigns, where I often used adapted modules but made up most of my own monsters. I want to focus on building more original dungeons from the ground up. Also, I want to play test the Hexagram rules, and parts of the setting have been tuned for that purpose. For example, I would be lying if I said that the setting backstory of embodied divinities was not largely influenced by my desire to have many gods available for the covenanting rules.
This brings me to the gods of the setting. If you have been reading my sporadic notes, you may have noticed that I am using many historical deities. For example, both Hades and Osiris are likely wandering around the setting somewhere (and likely at odds, given that they both claim to be lord of the underworld). Part of this is me wanting to use Deities & Demigods as a monster manual. This approach is also influenced by the unapologetic abandon with which many anime and manga drop different cultural elements into a blender. In terms of setting metaphysics, the Great Conjunction merged many or all deific conceptions with material reality, including potentially those from other possible realities. Which is to say, Hades does not imply an identifiable Greece analog within the fictional world. In general, I prefer syncretic fictional cultures over direct references. Though I realize the practical benefit of being able to say Fantasy Japan (or whatever), with a few exceptions (like Hyboria or the Warhammer Old World) I tend to find that kind of setting less interesting.
This is a lot of telling rather than showing, and I hope the various principles come out more naturally within setting materials as I develop them, but I find it useful to state these things directly both to use as personal guidelines and to give players a sense of what key to play in.