Space is getting grander and more interesting thanks to the Utopia dlc for Stellaris, and Crusader Kings II is receiving a rabble of Monks and Mystics next week, but Europa Universalis IV [official site] hasn't been left out. A tenth expansion is coming. It's called Mandate Of Heaven and it adds an objective system based around semi-dynamic ages (from Discovery to Revolutions) to the world while introducing new mechanics for the Empire of China, daimyos and Shogunate of Japan, and Manchu.
The Mandate of Heaven is in the game currently, causing the Ming Dynasty to collapse into a death spiral if they lose it. Essentially, it means that the Emperor is considered an appointee of the divine, legitimised by the gods themselves. It's impossible to be any more legit than that, but if the mandate is lost, the entire Dynasty finds it extremely difficult to recover.
In the expansion, handling of the mandate and its power will be far more involved, allowing the use of powerful divine edicts, and negating the need for legitimacy entirely. Instead, the Empire of China will use Meritocracy, a system of power tied directly to the skill levels of advisors. There are other changes in that part of the world, including the use of tributaries and a revamped Confucianism, but the biggest changes might be in Japan.
Paradox are rebuilding Japan in the image of Sengoku, their 2011 strategy game. The spread of Western technology and religion, isolationism, a war of unification and control among the daimyos, and a harmonisation mechanic that rewards the Shogun who can keep everyone on the same page. The unification of Japan sounds like a game within a game.
Globally, there are now four ages to move through, each of which comes with objectives that unlock new abilities, which are only available in a single age. Once the world (and your nation) moves on, the ability is lost. Some of the abilities are unique to certain nations, but there are seven generic ones for each age.
Mandate of Heaven also brings some smart UI modifications and a whole bunch of other changes, which we'll look at it in more detail shortly.