If python code improvements were free, I’d favor some easy-to-use feature that let voters optionally explain to the comment-author the reason for their up- or down-vote, anonymously. With the explanations visible to the author but not to the rest of the world (or not to the rest of the world unless the world clicked?), and so not cluttering the thread. Explaining the up-votes would let people spread goodwill, and point out specific strengths that the commenter could perhaps extend; explaining the down-votes would let people help new users learn to write useful comments, and would keep criticism less discouraging. (It is easier to respond well to “you should do such-and-such” than to blank rejection.)
But, yes, mandatory explanations would be terrible, as would a norm in which explanations were expected to accompany down-votes.
If python code improvements were free, I’d favor some easy-to-use feature that let voters optionally explain to the comment-author the reason for their up- or down-vote, anonymously. With the explanations visible to the author but not to the rest of the world (or not to the rest of the world unless the world clicked?), and so not cluttering the thread. Explaining the up-votes would let people spread goodwill, and point out specific strengths that the commenter could perhaps extend; explaining the down-votes would let people help new users learn to write useful comments, and would keep criticism less discouraging. (It is easier to respond well to “you should do such-and-such” than to blank rejection.)
But, yes, mandatory explanations would be terrible, as would a norm in which explanations were expected to accompany down-votes.
Agreed—even just functioning private messages would be a fix for this.