I think you have some good points, although I don't know that the downvote should always be viewed as a punishment. For instance, if I see a snarky comment and

I think you have some good points, although I don't know that the downvote should always be viewed as a punishment. For instance, if I see a snarky comment and I downvote it, it's not so much that I want to "punish" the snarky commenter (I might even find the comment enjoyable), rather it's just a piece of feedback that I don't think this is the appropriate place for snark. So in that usage I think the downvote is fine, I just want people to know why that vote was made. Plus then, I think you sort of need the downvote to balance out the upvotes of people that upvoted the snarky comment because they enjoyed it without thinking of the larger ramifications it has to the site as a whole.