It's a dictatorship of some kind, that's for sure... on what precepts, that's open for debate.
You control everything. What you build. The military decisions. Where people should live. No social movement, no ideological factions, no elite class can obstruct your power. The only thing that will cause your society to change is a sort of nationalistic-greed: will this make our nation better? Nationalism trumps some kind of global morality. Nationalism trumps the interest of separate social classes.
You also gain the money from the holy city of the religion, and decide whether to adopt that religion, and how -- do you believe in charity or do you believe in war? Your people don't care about the doctrinal or moral issues of religion either. They just shut their mouths and go to church every sunday. It's beliefs without acts:
dead faith. If you build them a temple, they are pacified. It suggests that you might be a religious dictator who is never wrong.
There are some exceptions. There's some token ethnic-nationalism that will spark a resistance in any city you conquer. There's some token war weariness if war goes on too long. People get a little mad about being enslaved.
A theocracy would ALMOST make sense. Except that you love science. In fact, you get to decide what to discover next. Theocracies tend to be very fearful of science, from global warming and genetic engineering today... all the way back to hostile views against astronomy. Theocracies even opposed banking. I guess it makes sense, though, because you use religion as long as it serves you, and then let it sort of fade into the background.
In other words, it's neoconservatism. Leo Strauss is a perfect example. Here's an
objectivist website (note, I'm not an objectivist or a libertarian) contrasting Leo Strauss with their own philosophy:
Here are the main points of Strauss’s philosophy. Except for one quote of Strauss, as noted, all quotes are of Ms. Drury describing Strauss’s ideas.
# There are the rulers and the ruled; “those who are fit to rule are those who realize there is no morality and that there is only one natural right – the right of the superior to rule over the inferior.”
# This elite must perpetually deceive those they rule.
# Religion “is the glue that holds society together.” Any religion will do. “Secular society … is the worst possible thing,” because it leads to individualism. “You want a crowd that you can manipulate like putty.”
# “... a political order can be stable only if it is united by an external threat; and following Machiavelli, ... if no external threat exists, then one has to be manufactured.”
# “Because mankind is intrinsically wicked, he has to be governed ... Such governance can only be established, however, when men are united – and they can only be united against other people.” (Leo Strauss)
To sum up: Strauss advocated a benevolent aristocracy that keeps its citizens in line using religion, deceit, and perpetual war.
Sounds a lot like Civilization. Except keeping your citizens united is a lot easier than he described. You really only need some dyes and wines, some smart civics choices, and some temples. Have a democracy, but lie to people about it so you can keep controlling everything. Just remember to pay that maintenance, and keep your wars short.
Would I suggest changes?
It might actually be more fun if you really had to work to keep your people unified. I'd love to play a game of civilization where you need to work for your peoples' support -- and sometimes try to draw your support from a powerful minority who will keep the other people down. But the truth is the few examples of people resisting you are considered annoying to a lot of people: unhappiness from slavery, war weariness, maintenance for large empires. Adding more factors like unhappiness-between-religions or unemployment and homelessness would probably just annoy people.
It's a thin line between adding fun gameplay and adding annoying obstacles.
