About the "fall off the front page before many readers see them" problem: that's a serious problem, as the discussion is what makes HN such a great place. Maybe reduce the options to "downvote" a news. It should be enough to upvote a news. If a news fall of the frontpage because certain members don't like it, they shouldn't be able to downvote such news in the first place.
Maybe the date time (UTC) like https://qht.co/front?day=2016-01-26T08 to view the frontpage as it looked like at 8 am UTC that day. ( ISO date and time: https://en.wikipedia.org/wiki/ISO_8601 )
About the "fall off the front page before many readers see them" problem: that's a serious problem, as the discussion is what makes HN such a great place. Maybe reduce the options to "downvote" a news. It should be enough to upvote a news. If a news fall of the frontpage because certain members don't like it, they shouldn't be able to downvote such news in the first place.