Phyletist tendencies can be risk, sure.
I’d say any parish is ethnic though. Groups from the mirror the culture of the dominant ethnic group in America just get perceived as “non-ethnic.” Being the child of immigrants and also a convert, I must say that the “non-ethnic” OCA and Antiochian seem just as ethnic to me as the parishes of Russians, Serbs, etc. They just happen to be “Anglo-American ethnic.” I have asked other converts who are not assimilated into the dominant Anglo-American culture; it loooks the same to them too.
Catholic and Protestant churches are very ethnic too. I will own up to the issue of phyletist tendencies, but I cannot agree with the stereotype that Orthodox are more “ethnic” than Western Christians. We are just often the “wrong kind” of “ethnic.”
*Also, I might add that nationalism is very interwined with conservative Christianity in the US. Is the Christian Right really less nationalist than the Russian Orthodox?
It is not a strictly Orthodox problem.