Actually, I think highschool teachers with accents are more troublesome. Because students actually have to communicate with them on a day-to-day basis. Whereas in university, most professors generally just use powerpoint and read off the slides.
However, in discussion groups where the class size is smaller and the professor actually has to talk with the students, accents are more of a problem. It's not really possible for the university to hire teachers based on their accents, so I guess the only thing for students to do is hope that the professors in their discussion groups can speak English well.