I still get a lot of value from HN, but possibly more from the submissions than the comments. Sometimes there's gold in the comments, but it's questionable if the signal/noise ratio, and the time to dig for it, is worth the effort.
The fact that people come out and take time to share their own experience is very valuable. There are not many places like HN. Most of the rest of the internet is filled with trolls, maybe that's what people prefer?
I don't get your signal/noise ratio statement. Comments are not only for you. They aren't a blog post. They are opinions, thoughts, experiences, of a lot of people. You can't apply such a thing as signal/noise because what to you seems as noise might be very valuable for someone else.
Plus any reply that's not the top reply is not shown adjacent to the comment it's replying to, which can make the discussion hard to follow. (Not sure there's a solution to this since we read linearly but a group discussion like this does not have a linear structure.)
I still read and enjoy the comments but it's a "choppy" experience in terms of context and that can leave me feeling dissatisfied when ideas don't have a chance to develop or really go somewhere.