Comment by ibejoeb

I've observed that simple, positive feedback like "Looks good, keep it up" gets downvoted as nonconstructive. Karma is more than internet points here since the thresholds drive so many features, so I bet people who would otherwise comment in the affirmative simply don't. Paradoxically, nit picking and verbose argument can score a lot.

I don't want to offer any particular suggestion because I don't have any data to support anything. A hunch, though, based on your idea: if someone want to downvote, a comment must be provided.