Ideas of posts I could write in comments. Agreevote with things I should write. Don't upvote them unless you think I should have karma just for having the idea; upvote the post when I write it :P
Feel encouraged also to comment with prior art in cases where someone's already written about something. Feel free also to write (your version of) one of these posts, but give me a heads-up to avoid duplication :)
(some comments are upvoted because I wrote this thread before we had agreevotes on every comment; also I'm removing my own upvotes on these)
Lead with the punchline when writing to inform
The convention in a lot of public writing is to mirror the style of writing for profit, optimized for attention. In a co-operative environment, you instead want to optimize to convey your point quickly, to only the people who benefit from hearing it. We should identify ways in which these goals conflict; the most valuable pieces might look different from what we think of when we think of successful writing.
Writing to persuade might still be best done discursively, but if you anticipate your audience already being sold on the value of your information, just present the information as you would if you were presenting it to a colleague on a project you're both working on.
Agree that there's a different incentive for cooperative writing than for clickbait-y news in particular. And I agree with your recommendations. That said, I think many community writers may undervalue making their content more goddamn readable. Scott Alexander is a verbose and often spends paragraphs getting to the start of his point, but I end up with a better understanding of what he's saying by virtue of being fully interested.
All in all though, I'd recommend people try to write like Paul Graham more than either Scott Alexander or an internal memo. He is in general more concise than Scott and more interesting than a memo.
He has several essays about how he writes.
Writing, Briefly — Laundry list of tips
Write like you talk
The Age of the Essay — History of the essays we write in school versus the essays that are useful
A Version 1.0 — "The Age of the Essay" in rough draft form with color coding for if it was kept