However, in the past there have been some Russians, Germans and Eastern Europeans with very strong accents, even some of them having being academics, who have been let go quickly on account of complaints from their students.

The Chinese do not like strong English accents!

Some of us do speak with strong English accents(not me) but we are fully understanding of the language as only a natural-born-speaker can be- whereas Ivan has a strong accent but no saving graces. Most native-speakers with strong accents manage to tone it down for the classroom. In UK we have a richness of accents and foreigners should like it or lump it.