Downvotes Should Require a Meaningful Comment
I'm sure the response to this suggestion will be predictably something along the lines of 'what is a meaningful comment'.
It's simply, anything other than just entering a string of random text to full-full the length validation. That's it. An actual sentence.
If it's rubbish, great, that's still helpful because the original poster of the downvoted comment knows the time and effort they've put into writing a thoughtful comment still stands; meaning the downvote was bullshit, petty, or just flawed reasoning.
There will always be people that are going to downvote just about anything. And of course this will limit knee-jerk downvotes, along with causing one to pause before doing it because they'll be open to a downvote if their reason for the it is flawed.
I predict if this comment gets any traction it'll quickly get flagged. That's the next most common way for people to shut-down conversations they don't agree with.