> There are professors whose teaching quality is actually proficient and sometimes excellent, but whose student evaluations are marred by the fact that they can't speak English well, they have social deficiencies (e.g. Asperger's syndrome), etc

And those teachers deserve to have lower student ratings, because the quality of the experience for the students is drastically lower even if they learn the material at relatively the same level of competence. I myself have social deficiencies, and I don't expect people to give me sympathy points if I ended up lecturing a large class.

I fail to see how anything you've written about Coward's "cult of personality" is bad at all.