In my opinion, choral works that cannot be sung by the people have no place in a parish. In a catheral-- maybe. Choral works that can be sung by people are okay. Znameny and other original chants--those are still the best, however.
Here at St. Vlads we use all English (although honestly I wouldn't mind a little Slavonic, but we have Antiochians, Greeks, Africans, Japanese, etc. here so English is it), and we do use some choral works. The choral works used though are simple enough that people can learn them and sing them if they choose.
As someone remarked to me, it is wrong for no one in the congregation to sing, but it is equally wrong for reformers to force everyone to sing. Some people are just not used to it.
I once heard the argument that one cannot sing Byzantine chant congregationally. I told them to visit Holy Transfiguration Melkite Greek Catholic Church, where they sing Byzantine Chant congregationally. Now only the choir of chanters does the stikhera at Vespers, but that to me is a cultural preference that could be overcome as well--I oftentimes find myself, when knowing the text, singing right along.
As far as Russians and their polyphonic singing--even this can be maintained in a congregational sense. One option is to have the people grouped together for parts. That might not work if you don't have a close-knit community. Another is to have only 2 parts: melody and drone, which works well with Obikhod melodies. A third option is to have the choir lead and people "pick" their parts, which can be done if they people are supplied with music books.
Liturgy literally means "work of the people" and if no one in the congregation is participating in even a Lord have mercy, you know something is wrong. I'm not saying you'll be able to change things (for instance Serge's comment that NO ONE at his parish in the congregation sings--how are you going to change older generation Russians?), but that nevertheless no participation by the laity is NOT healthy and NOT the Eastern ideal.