HN already prevent submitting the same link in a short time frame. Quite often, submissions can end up without activity and resubmitting helps more people contribute to the discussion.
Topics aren’t “finished” just because /some/ HNers discussed it one day.
Right but couldn't that type of system be roughly accomplished by looking up the canonical URL and/or title from the meta tag (from a scrape) and search against the last posts?
Having a stronger policy on repeated duplicate offenders should be a thing. It just farms points that can be later used in a bot farm.
I think submission quality would improve if people were forced to lookup if the topic has already been discussed.