As I think the next version will be really AMAZING: Make OTTOMANS GREAT AGAIN
Also there are a lot messages which promote an idea to DIVIDE Kievan Rus on the one hand and Moscovia (Russia) on the other hand
P.S. by the way Germany/Prussia and Khmer/Thais already had such mechanics
Russia shall spawn as Kiev, collapse under Mongols and respawn at Moscow. Human player can just survive the Mongol attack (and maybe be request by UHV to transfer the capital in Moscow). Actually it is pretty doable under current mechanics.
However, I would like to see Sankt-Petersburg as capital in Renaiscance era, so AI Russians have 3 capital locations which isn't doable straight away.