I would like to see more finely-grained feedback than just "no". Particularly as it forces the voter to justify why they're downvoting.

Some posts/contents are bad because they're spam, abusive, or against the rules, or in the wrong place - downvoting these is useful crowd-sourced moderation, particularly for things that don't warrant a mod report.

Some are just indisputably wrong and it's a useful signal that the poster is talking rubbish. Then there's the grey area.

Sometimes it's just that the poster's opinion is unpopular, and people are downvoting to suppress views they disagree with - I think that's not a good thing for a discussion and encourages echo chambers. I like the idea of one of the downvote options being "I disagree" and that basically not doing anything.