In writing, the reader is often remote. In formal writing, the writing represents a final recorded thought.
This is an important idea, that might be hard for this generation to understand. I'm old enough to remember before the internet, when information came from books, newspapers, magazines, and the like.
These were carefully architected pieces of writing, consisting of a central thesis pitched to an editor, the editor tweaking the idea and making suggestions for key points to cover, the writer doing the research and writing the first draft, the editor responding with notes, and then a final version penned, which was copyedited by a professional, proof read, laid out, type set, and printed, then reviewed again.
But that kind of writing rarely - if ever - still happens. Even my friends who write for The Economist only get one pass by an Editor nowadays.
So - and here's my central musing - in the era of words-on-the-internet, is it a proper assumption that "formal writing represents a final recorded thought?"
Tweets get deleted constantly. Blog posts and news stories get edited after being published, without any notification that the content has been changed. Scientific papers are routinely proven to be complete fabrications, heavily slanted, or undergo heavy revisions after publication. Books on the non-fiction shelves today have proven to be total fabrications (Mutant Message Down Under, 1421: The Year China Discovered the World), and every mass-market book (ignoring all the self-published dreck out there) you pick up today is riddled with so many copyediting errors they can actually be hard to read, or the author's point can be completely muddied. Etc...
So... in this day and age, what is "formal writing"? Your dissertation that one, possibly two people, will ever crack the cover of, scan through briefly, and then never open again? Papers written for schoolwork that add nothing to world's knowledge or canon?
(Just to be clear, I'm musing off the top of my head, asking the questions that I find there... not commenting on your teaching style or intention. I, for one, am someone who greatly treasures the written word, and beautifully crafted sentences and ideas. I mourn the loss of editors and the amazing writers they honed and polished to a shining finish.)