Seconded: the comment stream should be a professional forum.
I notice that the comment page requests us to be polite, respectful, and informative: these are the values of the site, and comments should conform to those values.
I filled in the user survey, and hated having to note that I was considering not renewing. In fact I hope to remain a subscriber - the articles are excellent, as are the best comments - but if I have to wade through flame wars, if I can't shape what I see and if the editors can't help me, if I stop reading because it's not worth it, then at some point I'll stop paying.
Personally, I read the RSS feed, and that works well if the noise level is tolerably low. Previously I read the comments in context, but that works best if I wait for a week or ten days, which is not a good bargain.
So, two ideas, not new:
Keep the noise level down: by suitable in-band prompting, private messaging or selective defacement.
Help the subscriber to read the comment stream in context: Support a kill-file, have a per-user RSS feed to allow per-article feeds, have a per-user per-article last-read date to offer a per-user page of articles with new comments.