The intrinsic problem is you have a finite amount attention and an increasing number of startups. I'm not sure how much aggregated threads actually solve that (not at all IMO).

I think you just let them go at it with Launch HN's and let the upvotes fall where they will.

Re: Writing Launch HNs -- My idea: set a lower character limit on what they're allowed to submit and you'll have less to edit. If there's more information that people want to know, create the expectation that they should just ask in the comments.