Personally, I find the Sequences, both individually and collectively, to be a model of clear writing. But they're not at all terse, are they? Yvain writes long blog posts that I'd put above Eliezer's for quality of writing. Moldbug writes at insane length, and yet always very readably. But then, some other long posts I find myself thinking, oh, get on with it, get to the point already, whatever the point is. Or they just say the same thing in ten different ways, as if adopting Paul Graham's advice on how to seem articulate. I can't give examples because I don't pay much attention to those.

Short vs. long is not the issue. Structure is the issue.

perhaps experienced rationalists here could write nice and concise posts that give short and clear answers to complicated questions

I'm not interested in short and clear answers to complicated questions. Or to put that more tersely, I'm not interested in answers on their own. My reaction will be, "That's nice, but how did you get there? Why should I care about your bald pronouncement?" It's like being given a purported map of buried treasure that is just a blank sheet of paper with an X marked on it.