Ideally, the benefit would be receiving feedback at multiple stages of the writing process.

At idea conception, I'd like good feedback on whether an idea is interesting and worth pursuing further or obviously flawed or already covered (there are way too many posts for someone who's not been here for years to be aware of all of them, and search is only sometimes helpful). After that, it may be good to get quick comments on an outline or choice of style (e.g. "you should try to make it less dry" or "you need to spend more time explaining the importance"). Once the post is completed, it would be valuable to know whether the end result is good/salvageable/how it can be improved (e.g. I have one post up, and I recall that after posting it, there was instantly a comment at like +10 saying "this pair of sentences is stupid" and then I realised that it was indeed stupid and I shouldn't have included them - having someone point that out before I posted would've helped). All of this preferably without even potential karma losses to avoid creating ugh fields or even general worries.