I think this is a radical idea, but hear me out: I fully believe the community could be better curated if they took the down-vote button away. (Or, at least, reserved it for the highest echelon of users)

Looking from the island of HackerNews, back to the continent of Reddit where I wasted so many years of productivity, I've seen amazing wonders in the way HN uses its down-vote systems. In essence, it's there to "nudge" the discussion back into the right direction, and overall a great tool for curating a community from those that have been decided by their peers to curate.

To me, a down-vote button puts an undue weight on the negativity of a discussion. There's three states: "I liked this", in which you up-vote, "I didn't like this", in which you ignore it, and "I didn't like this", in which you down-vote. Even reddiquette dictates that it should only be used for anything that doesn't contribute. It's very clear that's not how it's used, and in my opinion that can only be fixed by changing the official meaning of the button or restricting its use altogether. I think the latter has amazing effects on community discussion, as I've seen here on HN.

Stuff I know I didn't discuss above: The effect of a non-focused forum discussion, abuse in voting systems, impacts of large communities.