I was thinking about slashdot modpoints too - it did seem to result in better discussion, but maybe everything was better in those days/in my rose-tinted spectacles. (And at this point I cba going back to check…)

There were some oddnesses - I remember someone’s signature was “The difference between ‘Interesting’ and ‘Insightful’ is whether you agree” which always rang very true to me. Separating upvotes for “funny”, “I agree” and “I find this interesting” is already pretty handy though.

I think there’s no way to prevent people from downvoting what they disagree with - but maybe if you provided downvotes for “this is wrong” and “this is trolling” people could have an option to ignore the “this is wrong” downvotes and get more diverse opinions.