People, you all "think" too much. 
The fact that Russians controlled (hardly owned) eventually most of the steppe doesn`t mean they also were able to colonize it. Indeed, partially they did colonize. Where? In siberia and upper Volga-territory. The first is possible and easy to do as the territories are uncolonized, the latest is unnecessary as the provinces of upper-Volga start already as Russian in 1419 (which is thus disputable whether they should). All other territories were either not colonized in the eu-timescale or not colonized at all.
The following provinces should have in fact no Russian culture in the game (while they have in eu)
-Kazan (if we consider the city of Kazan the capitol at least - it was not russified before ~1850 or so)
-Ufa (was inhabited by Mongols and even Peter the Great has forbidden Russian colonisation there)
-Volgograd (highly disputable for 1419, Russians never colonized it before ~1600 and probably not even then. The military border went to the north of it)
The same accounts for Samara.
Then the military border went through the pti in Urals and ended in Semipalatinsk and Tobolsk. Tobolsk is pagan and thus convertable, Semipalatinsk is uncolonized. All territory to the south was not inhabited by Russians, and only to the slight controlled before ~1800 (Astrakhan being an exception as there was a military forpost there).
So that means all the Crim, Azov, Kouban, Kalmuk, Orsk, Odenburg, Kurgan and Magnitogorsk Nogai-territory, Kazak-territory, and the farther steppe and caucas were not Russian controlled till 1800 at least (apart from a few forposts acquired in 18th century in Crim and Azov) and there is no point for either change of culture or acquiring of another culture by Russians.
That brings btw also the question if the Russian cb-shields are correct for the steppe. To my opinion they aren`t. Most Uzbekh and Kazakh territory was again not Russian before ~1800. The Amur-territory in east-siberia was chinese controlled till later 19th century. Otoh the Crim became partially Russian after 1750.
The fact that Russians controlled (hardly owned) eventually most of the steppe doesn`t mean they also were able to colonize it. Indeed, partially they did colonize. Where? In siberia and upper Volga-territory. The first is possible and easy to do as the territories are uncolonized, the latest is unnecessary as the provinces of upper-Volga start already as Russian in 1419 (which is thus disputable whether they should). All other territories were either not colonized in the eu-timescale or not colonized at all. The following provinces should have in fact no Russian culture in the game (while they have in eu)
-Kazan (if we consider the city of Kazan the capitol at least - it was not russified before ~1850 or so)
-Ufa (was inhabited by Mongols and even Peter the Great has forbidden Russian colonisation there)
-Volgograd (highly disputable for 1419, Russians never colonized it before ~1600 and probably not even then. The military border went to the north of it)
The same accounts for Samara.
Then the military border went through the pti in Urals and ended in Semipalatinsk and Tobolsk. Tobolsk is pagan and thus convertable, Semipalatinsk is uncolonized. All territory to the south was not inhabited by Russians, and only to the slight controlled before ~1800 (Astrakhan being an exception as there was a military forpost there).
So that means all the Crim, Azov, Kouban, Kalmuk, Orsk, Odenburg, Kurgan and Magnitogorsk Nogai-territory, Kazak-territory, and the farther steppe and caucas were not Russian controlled till 1800 at least (apart from a few forposts acquired in 18th century in Crim and Azov) and there is no point for either change of culture or acquiring of another culture by Russians.
That brings btw also the question if the Russian cb-shields are correct for the steppe. To my opinion they aren`t. Most Uzbekh and Kazakh territory was again not Russian before ~1800. The Amur-territory in east-siberia was chinese controlled till later 19th century. Otoh the Crim became partially Russian after 1750.
