I'm kind of not liking the way the author has gradually transformed the art style of sensei's face. It feels to me like she is becoming a generic-ish moé-blob character with large, circular eyes and overly cutesy face. It gives me the impression that too many of her edges are being softened.
VS
I mean, on the one hand, it makes sense since her personality is softening, but on the other hand, a personality change should not transform one's eyes from ovals into circles. (lol)
I personally prefer her initial, less moé face. But well, that's just my opinion.