This "teach writing in every class" idea is so commonsensical that I wonder why it hasn't been done always at every college in the country. The fact that it's such an innovative concept that they have to give it a name is a little sad:
Most of my faculty colleagues agree that Writing Across the Curriculum (WAC), in which the task of teaching writing is one assigned to all professors, not just those who teach English or composition, is an important academic concept. If we had a WAC playbook, it would sound something like this: students need to write clear, organized, persuasive prose, not only in the liberal arts, but in the sciences and professional disciplines as well. Conventional wisdom and practical experience tell us that students’ ability to secure jobs and advance in their careers depends, to a great extent, on their communication skills, including polished, professional writing.
[. . .]
The WAC playbook recognizes that writing can take many forms: research papers, journals, in-class papers, reports, reviews, reflections, summaries, essay exams, creative writing, business plans, letters, etc. It also affirms that writing is not separate from content in our courses, but can be used as a practical tool to apply and reinforce learning.
More controversial — and not in everyone’s playbook -- is the idea that teaching writing skills cannot be delegated to a few courses, e.g., first-year composition courses, literature courses, and designated “W” (writing-intensive) courses. Many faculty agree with the proposition that writing should be embedded throughout the curriculum in order to broaden, deepen and reinforce writing skills, but many also take the “not in my back yard” approach to WAC.
Elsewhere in the article is the line "writing is thinking made manifest," and I've even go a little further. Learning to write well, which requires you to organize your thoughts in a coherent order and draw logical conclusions from reasonable premises, actually improves your ability to think well. It's amazing to me how many would-be journalists I've seen over the years who not only didn't write well but could barely string together a few simple sentences into a rudimentary paragraph.
WAC is still controversial? I suppose some would make the argument that in the era of texting and tweeting and voice recognition, writing skills are becoming less important. But because tehcnology allows writing skills to get rusty, I'd say WAC is more needed than ever. What kind of thought processes would you expect from someone whose main writing involved 140-character bursts? How comfortable would you be with somebody like that on the job with you?
