I agree with #1. It's super easy to write a blog post that gets more upvotes than any comment ever will. If most HN readers are like me, I immediately go to comments before checking out the article. The current karma system encourages posts over comments, while comments are actually the vast majority of reason we visit HN. Comments are the community, especially in recent years where ask and show hn posts rarely breach first page :'( . Weighting non-article posts higher would achieve similar, bringing back importance of community over posting stuff.

I also agree with #2, a single unpopular comment can ruin your karma, and seems to rapidly contribute to a rate limiter that impedes your ability to interact with the site. I tend to comment on spurts when I've got a bunch of free time. It's common to have a comment downvoted below 0 and end up with "you're doing that too fast" rate limiting. I'm not 100% that downvoted comments are the cause, but it seems likely.

I disagree with #3. The few mods HN has already work hard. I don't think we should give them more to read. I would rather remove downvotes, I don't see a point besides encouraging echo chamber mentality