"Time to start flame about Eastern Slavic cultures. 3 second before start of flame... 2... 1... go!"
Let's go!
I'm truly uncertain about the cultures... Don't they look far-fetched? The Rutenian culture is incredibly important. It allows us to simulate the real historical process, showing how the Ukrainian and Belarusian identities developed in western Rus. But what are the Novgorodian, Muscovite, and Severian supposed to symbolize? Moscow's expansion is only beginning, so why are the surrounding principalities, even hostile ones like Tver, also labeled as Muscovite? Honestly, this feels like a gamey choice, and I believe the Caesar project shines best when it leans on history, not when it tries to fit history into gameplay.
We have a wealth of historical data indicating that in the 14th century, the Eastern and Western Rus languages began to diverge into two distinct languages. From the Western language, Ukrainian and Belarusian would later emerge. However, there was no significant split in the Eastern Rus language. Yes, there were various dialects, but the differences were minor.
I understand that portraying the cultures of 14th century Rus is a complex issue. Due to the assimilation efforts by Moscow later on, many cultures did not survive to the present day. But wouldn't unified Rus culture be better choise? Similar to the case with Ruthenia? This would be a simplification, but a logical one, unlike the invented cultures of the Muscovite, Severian, and Novgorodian. It might disrupt the balance, as there would be a large, unified culture in this region from the start. But wouldn't that make the region more unique? And this uniqueness would be dictated by history, not gameplay reasons, which I see as a win. We already have a historical political division in the region. Is it worth putting an artificial cultural division on top of it?
As an alternative, I would make several cultures in the region, but mix them up in the locations. We will take the peoples who lived on this territory before the emergence of Kievan Rus, and show that during its short existence, the principality did not assimilate all these people (as in reality it was). There will be several cultures in the region, and while playing in this region, the player will have to assimilate them. But the player will face this task when playing for any principality, be it Moscow, Tver or Novgorod. And it won’t be that Novgorod will start with its unique Novgorodian culture, and Moscow with its Muscovite...
In any case, I am not a historian, just an enthusiast. But as someone with a great interest in this region, the cultures currently presented in the game seem contradictory and illogical to me... Perhaps someone more knowledgeable could provide a better alternative.