The AI isn't great with exploration. While I prepare a maximum of army commanders, settlers, and scouts to cross the ocean as soon as cartography is researched, the AI usually just explores with ships first, and doesn't do much else until they got shipbuilding. By that time, my aggressive move into religion has given me a huge boost to science, so the AI is way behind in shipbuilding. And I have already most of the new continent mapped, and treasure resources secured either by settling or by conquest, before the AI even sets foot there.

The modern age is even easier. Even after the patch, the culture victory is still relatively easy, although now the economic victory is sometimes faster. The game tends to be over before even all AI has chosen an ideology, which makes a military victory not really feasible. And the cultural or economic victory are so fast, that I never get around to a science victory, although I am leading in science as well.

In short, the challenge of Civilization VII is currently ending in the antiquity age, because the AI is so bad at the other ages. So I was wondering whether the AI was doing anything at all. So I played a game deliberately badly: I played an extremely isolationist Carthage with a strange special rule: None of my units every left the area of the city, never got more than the 3 spaces away from the city center. That meant no scouts, no merchants, no contacts with city states, no conversion of other cities with missionaries. Just relatively fast moves, because most of the map was covered in fog of war until the very end. The only really interesting thing was that if you are weak like that, all AI players are going to declare war on you with no reason in modern age, probably to try and gather ideology victory points. But defense is very strong in Civilization VII, so with a bunch of guns behind city walls I was able to beat back all AI players at once, until they gave up and made peace. Finally some AI actually won.

What that single settlement game showed me, was that the main problem with not expanding is that you need additional towns for gold, and additional cities for more science and culture. You do have enough production to build every building you research, but progress in technology and civics is slow. You can easily defend against any aggression, but that is mostly because the AI is so horribly bad at warfare.

For my next game, I plan to do the antiquity normally, and then play the age of exploration without religion. Or rather, without missionaries, as you can't really avoid researching piety. That is obviously sub-optimal, but that way I don't crush the AI with a runaway success in religion in that age, and that makes the game maybe a bit more balanced. Unlike Millennia, there doesn't appear to be any negative consequences if you let the AI convert your cities. And the whack-a-mole later gameplay of missionaries is boring and annoying anyway.

To me it appears as if one of the fundamental balance problems of Civilization VII is that features like religion or archeology give such huge rewards for rushing them. As the AI isn't good at throwing all their resources at a single issue, that massively favors the player. After a couple of games, the player knows which game elements he should rush to, and then winning becomes trivial.