I'm following Civilization VI's civilization design philosophy, wherein civilizations are a coalescence of different polities across different times connected through culture and geography.
You can see this in Indonesia, India, China, Korea and now, thanks to the Leaders Pass, Persia as well. Indonesia as portrayed in the game would more appropriately be called the Majapahit. But the fact that it is called Indonesia makes it possible for a leader like Hasanuddin of Gowa to lead the civilization, thus showcasing Indonesia's multireligious multiethnic history. For Korea you have Seondeok who was only the ruler of one of multiple states that make up Korea. Only recently has the Civilization series acknowledged the post-Achaemenid history of Persia. As for India, I am thinking of making a list of various Indian leaders from across history of different faiths and different kingdoms just to showcase how Indian history is larger than just Ancient India, Mughals and Gandhi.
One reason I like this approach is that we have more leaders and more representations of historical realms at the cost of fewer civilisations. This also allows modders to simply add more leaders to existing civilizations to represent important epochs and polities instead of having to create new civilizations from scratch, or waiting for Firaxis to give us a new civilization.