After doing more research regarding the Sheng situation and reading the actual words of the students, it definitely is a very troubling situation. Sheng obviously did not know his students very well, and his actions are quite bad. I taught high school for 3 years in the 70's and was a community baseball coach for 25 years from '65 through '89. I'm still in touch with many of my former students and players on Facebook. Sheng really fucked up. He has totally lost the confidence of his students. It's a sad situation.
I'm not an expert on Shakespeare. Othello is not one of my favorites and I've never seen a stage production. Ironically, when I was working on my masters at the University of Michigan in '74, I actually saw both the '52 Welles and '65 Olivier film versions of Othello. The films were shown by the university; however, I saw them strictly as a fan and not as an assignment.
Those were very different times and I liked both films. No mention was made about blackface then that I can recall. Seeing the films today, I think the Welles version holds up quite well, but the Olivier is quite dated. I still like his Hamlet and Henry V though. In general I still regard him as one of the greatest actors of all time. I think his performances in films like Wuthering Heights, Rebecca, Pride and Prejudice, The Devil's Disciple, and many others are still thrilling to watch. Just IMO.