Earlier quoted context omitted.
What if downvotes led to a popdown, with a series of radio buttons: ( ) I don't agree with this comment ( ) This comment is factually incorrect ( ) This comment is offtopic ( ) This comment is rude or inappropriate (Add and replace verbiage to taste, of course) Then people's downvotes would be imbued with some semblance of nuance. And get rid of the score, and make downvote categories have hidden negative values (so…
> Then people's downvotes would be imbued with some semblance of nuance. Downvotes or not for nuance or dialog, that's what comments are for. Downvotes are solely to demote content that is viewed, in the subjective opinion of the voter, as not contributing to productive discussion. If it deserves a nuanced response then it doesn't deserve a downvote.
Says who? It's not in the guidelines, so really when to use the feature is determined by its effects. Downvoting obscures comments and hurts a user's karma. So in reality, downvoting is to demote content you don't want yourself or others to see for whatever reason and/or to "hurt" (for lack of a better word) other users.
Your criteria of doing it based on whether it contributes to productive discussion fits in that, but it's not the only possible criteria users may determine for themselves.
mceachen's suggestion is to modify the effects to make the possible criteria space more narrow and more similar to the criteria you shared. When they see such a popdown, they'd have a better idea of what the downvote is meant to be used for. It would provide some guidance on the "proper" use of the feature.