> Russian just is not a great example of a Slavic language.
i am not sure what you mean but russian is by far the biggest slavic language in terms of number of speakers. i also think it is the biggest in terms of number of litterary and academic works
Having no neighbor to the east helped with that a bit.
From my west-slavic (Polish) perspective I can understand Czech, Slovakian (a bit harder) and Ukrainian semi-ok. But Russian is way, way harder (there are some similar words but most are alien to me).
I didn't have chance to listen to south slavic languages so I don't know how similar they are to west slavic ones.
All the Balkan Slavic languages also feel just like dialects. I could very easily converse in Polish throughout all Baltic countries. Along with the ones you mentioned. I find Ukrainian very difficult though. I'm not a native Polish speaker so I chalk it up to that.
> All the Balkan Slavic languages also feel just like dialects.
If you mean Serbian/Croatian/Bosnian/Montenegrin - they are only recognized as languages for political reasons. They actually are a particularly rich continuum of dialects but it is impractical to recognize this because it would imply there should be one literary norm.
When I was doing some canvassing for the election in 2016, I was able to use my limited Czech to speak with some Polish speakers. My grandfathers, one who spoke Czech, the other Slovene, both at a native level (they were raised bilingually in their ancestral language plus English) were able to understand each other. My father was able to leverage his Czech (another bilingual kid) to understand Polish and Slovene and he had a fairly easy time learning Russian.
i am not sure what you mean but russian is by far the biggest slavic language in terms of number of speakers. i also think it is the biggest in terms of number of litterary and academic works