There's been plenty of discussion and dozens of suggestions on how to make comments tidier / more limited / self-cleaning / auto-expiring. The option of hiding non-upvoted comments after 30 days has even been brought into play by Jeff himself if I remember correctly, and I think that's the way it's showed to non-logged-in users already.
No point collecting ideas again that won't be acted on anyway, and discussing the merits and problems of long comment threads - we've done that plenty of times and the result appears to have been "it's not big enough a problem that any change is needed". The problem has not changed fundamentally on our, the users' end - we've always had endless dicsussions in comments. It's just the number of questions with long comment threads that has grown, along with the overall number of questions, and that might have become a problem on the moderators' end.
If that's the case and you guys are drowning in comment garbage, then make yourself heard and complain. As it stands, this looks like one moderator's take on the issue. That is of course incredibly valuable insight in itself, but do the other mods feel the same way? If they do, they should all chime in and say, "this needs to change."
Why not emphasize that more clearly, and leave figuring out what needs to happen to the team. Otherwise the complaint will be watered down by just another round of well-meant ideas from us Meta users, and discussion that will lead nowhere.