I think the first Civ6 expansion is kinda imposturous in its title. Indeed, there are been ideas in this forum that pushed the idea of Rise & Fall of civs much more higher. One of them is the ability to continue to play the game when you have no more cities, for example. Let's say you are a civ, but in the way of an entity that is organic. More like the sum of your people, your culture, and your government. If you lose one of them, you could continue to play with various elements, like units or diplomacy. To obtain that, we would need something like a stability factor, but without governors. It is to say, nothing is eternal and you WILL turn into dust one day (turn) or the other. Now, the era score of R&F is interesting here. It could mean that you can achieve something in a relative small amount of time. And be reminded in the future as a great civilization, if not the greater. (numbers would conclude it) So my idea here is to have an ever-changing map when civs truly rise and fall, in front of the player, him included. That would require some chaotic factors, like less controllable "stability" or warfare, or more aggressive ones. Should we accept that by "chaotic", randomness could be a thing ? Maybe. The global idea is to have players that are trying their best in order to achieve something great, be it in antiquity, classical era, middle age, renaissance, modern, atomic or information era. And maybe why not, by an extraordinary concur of circumtances, in two of them. This doesn't mean you have to be dead in the other eras, you can be "revived" like Egypt, you can migrate and rule "emptied" places like Franks. (this means you can migrate and still be relevant), you can slowly grow in later eras like USA (that means means to grow in power rapidly, not only from the start to the end), and add any example to your convenience, pls. Thx. P.-S. : I think this is a vast subject, and I don't feel I can cover it up all the way myself only.