I think this is a key point. In my favorite writing course in college, the professor chose to teach composition from the perspective of legal argumentation. We wrote 4-8 pages per week in the most economical and intentional way possible, poring over every word, every sentence, and every paragraph to make the language easy to understand and to make every word do work.

The professor never pretended that this was the best way to write and never claimed the result would be beautiful, though he did claim that the result would be easy to understand, which it was. Peer editing in that class was the smoothest experience I've ever had in a writing class. But he accomplished something that no other writing instructor did for me before this class: he taught how to make grammar, diction, rhythm, and even connotation an intentional thought process. He also taught how to think clearly about the point you wanted to get across.

That wasn't going to teach any of us beautiful prose or how to craft good plots, but it got us very quickly to the point where our writing style became deliberate.