Adds internal politics in your country, with power groupings such as the Church, Nobility and Bourgeois fighting for control.
Adds the ability to interact much more deeply with the AI by setting your attitude and telling it what you want out of wars.
New religion mechanics focusing on Syncretism. Tengri have a secondary religion that they fully tolerate, and can change this secondary religion at will.
Horde Unity and Razing:
Hordes must attack their neighbors to secure plunder in order to keep the tribes happy, or risk a tribal uprising. Hordes can raze territories they conquer to get monarch points and raise horde unity.
Advanced Culture Change:
Adds the ability to choose what culture you want to convert a province to from any neighbouring culture, or restore the original culture of the province.
Adds the ability to set your policy towards the natives in your colonies, allowing you to focus on trade, assimilation, or subjugation.
Two new spy actions allowing you to study the technology of more advanced countries and agitate for liberty in your enemies subjects.