I read an explanation the other day about chat/comment threads (but don't seem to be able to find it again). According to that explanation, SE management wants comments to be topic related but finds that comments become chats. Therefor I propose the auto-chat feature. (I know there is a chat migration feature).
At this moment, when there are a number of comments, there is a link saying: 'click here to see more comments'. Instead of that link, I propose a link to a generic 'comment-chat room' for the next comments. The 'comment-chat room' can be shared by multiple questions and answers. The questions and answers are filtered thanks to the permalink of each question/answer.
This way, there will only be one 'comment-chat room' per SE site and the Q&A becomes less noisy at the same time.