...would result in popular opinions being promoted, without regard to their value...
I believe that's the case now. The only difference would be that, if you felt the existing top response was incorrect and there was no better post for you to upvote to try to overtake it, you would have to write one. I think that would be a positive development.
As much as HN is far from perfect, I still think there's some healthy disagreement visible and bad faith arguments don't get promoted.