You can't see the ratio, but if a comment has a negative score you'll see it, which I would count as downvotes being "visible" -- certainly better than YouTube'

You can't see the ratio, but if a comment has a negative score you'll see it, which I would count as downvotes being "visible" -- certainly better than YouTube's terrible choice here. Downvotes are also surfaced when the ratio is ~50% with a "controversial" marker.