My personal opinion is that downvotes, upvotes and algorithms are design decisions that often stick before the best one is found. It's a shame really, because I think it's not only really important (e.g. to combat fake news/users etc.) but most interesting. Nonetheless, HN did good with their version where the max. downvote of a comment is -4 and where the up/downvote of a comment is not listed publicly. All functions that help with community building. However, I fret the moment when AI users and shills take over (especially since throwaway accounts are so easy to create).