A few years down the road - as I know you guys will be engaged with FOG:E - but I just wanted to plant the seed:
Medieval Period - similar to Crusader Kings 2 - using the new engine (link to FOG 2 optional)
I picked up Crusader Kings 2 the other day in a Humble Bundle and said to myself - "All of this content and cultural flavor would be absolutely awesome - if AGEOD did it with their system".
Rise of the RUS
Fate of Byzantium
Expansion of Islam / Christian opposition
The development of many national identities that led to today's modern states ....
Would love to see this via AGEOD someday.
In the meantime, good luck with FOG:E.