When I teach screenwriting, I focus on the basics: story form, formatting, punctuation, spelling, and grammar. I keep the door open for good storytelling and creativity, but I don’t mark it.
The main reason is that it’s subjective. Just because I may not like it doesn’t mean it’s not good (and vice-versa).
Everyone also comes with different experiences and upbringings, and many aren’t equipped with the razzle-dazzle that some assume is creativity—although this isn’t the only type that matters.
Talent is overrated, and skills, creativity, and taste can all be learned.
Not by a teacher enforcing their personal biases, prejudices, and philosophies but by a student spending the time to improve on their own over their lifetime. Anything else leads to a creative homogeneity of the most boring kind.