Oh, were you thinking of doing this in private? I was assuming this would be out in the open, for all to see.
Yeah - the topic body could be the suggestion itself, and people could vote for it by liking it, and comment by replying. I don’t think it would take killer amounts of code to add a more prominent like count somewhere (like on the topic list page for the category), if deemed necessary.
I may be misunderstanding, but don’t likes (the heart you can press below a Discourse post) do exactly that: minimize the noise? I find it’s incredibly useful in existing discussions to signify your support for something, or acknowledge somebody else’s point, without having to create a new post.