The Brezhnev thing is not true though, the party was very meticulous about having the leaders of the SSRs belong to the dominant ethnicity of the SSR in question. What you might mean is that the 2nd secretary of an SSR was usually Russian and oftentimes sent over directly from Moscow. The Soviet Union was an incredibly multicultural nation in terms of its ruling circle make-up right up to the dismantling. Which does speak to a good popular representation among the delegates. The discrepancy in the levels of Soviet nostalgia has mostly to do with a post-Soviet revision of history and nationalist propaganda that ascribes all the "good" aka imperial attributes of the USSR to Russian national superiority and all the "bad" aka "the darn communist bureaucracy" to Communists and "internationalist degeneracy".