[technomancy]

I strongly disagree that there is any overall prerequisite relationship between the two fields. If you want to be a good writer, it's important to understand grammar, but telling children that they are not allowed to write at all until they've mastered a course in grammar is incredibly counterintuitive.

Learning needs to be holistic; you fill the gaps as you go.

[smonff]

Also you can be a good writer by knowing grammar intuitively and not being able to explain the formal rules.