He did explicitly point out that this culture of criticism / high standards makes writing for LW a chore

Let's bring in the entire quote. Yvain said:

Less Wrong requires no politics / minimal humor / definitely unambiguously rationality-relevant / careful referencing / airtight reasoning (as opposed to a sketch of something which isn't exactly true but points to the truth.) This makes writing for Less Wrong a chore as opposed to an enjoyable pastime.

Note that the first three points have nothing do with criticism. The fourth point is the requirement to show evidence which still isn't criticism. And the final point I read as having to be literal and formal with little "free play" in the moving parts -- I think there is a connection with the recent series of posts by Jonah Sinick where he talks how gestalt pattern recognition is, at certain level, superior to formal reasoning (and LW expects formal reasoning).

Yeah, I still think Scott Alexander could handle the downvotes just fine.

But to cultivate good content, it is not enough to just remove bad content.

I agree, but the suggestions offered tend to gravitate to "Let's just be nice to everyone"...

What kind of positive incentives to creators of high-quality content can LW come up with?