sharp dagger
After 4500 years of Antiquity, there couldn't be that much free space left on the map to settle a city. As the game transitions from Antiquity to Exploration, the map should get filled with independent nations. After that, you either conquer or raze to get new settlements.
They'll act as a buffer between you and the other civilizations as well as an additional objective. Maybe make it so they can form alliances as well to make it more challenging.
Another benefit is them settling land that you don't want. That island with one land tile and only fish resources? The tundra above you with decent resources clumped together in some spots? All settled.
It makes diplomacy a lot more important and changes the whole dynamic of playing in the Exploration age.
reef laurel