I would like it if all down votes required a reason for their down vote. I don't want to dissuade people from down voting, I just want to know where they feel I am flawed in my opinion. Maybe flawed isn't the best word, but I want to be able to understand what they feel is wrong about it.
Explanation of up votes wouldn't really be necessary since it would typically be explaining what was already said. Unless they want to add something to it.
So I wouldn't mind up/down votes on comments under opinions, but I would like explanation of down votes.
I don't get very many either side of votes, but I'm always curious about my down ones.
I think it's fine as it is honestly. The conversation threads that spring from someone responding to an opinion are only supposed to be within that particular thread, rather then taking up too much space.