Yeah, agreed. (My main hesitation is UI complexity, every feature you add adds a bit of overwhelm to the site)
FYI, for the immediate future, I sometimes solve this by self-downvoting my comment (and saying I did so at the beginning of the comment). Comments with karma <= 0 don't show up in Recent Discussion. People do sometimes upvote it later but typically after it'd already be lower in the recent discussion list.
Perhaps one of these strategies?
If I were implementing this, I would first look at a bunch of samples of comment chains matching the above queries, to see how well theory matches reality.
Can confirm, I keep reading and writing about high context drama, when I should be doing things that are not that.
Most forums work in a similar way: if you reply to a post, it gets bumped to the top of the feed. This is usually good, from the perspective of the commenter; people generally want others to see their comments.
There are obvious problems, though. On every forum with enough volume, there will be people who (deliberately or not) create reply-bait threads that drown out more interesting content. The best solution is not to reply - but people sometimes realllly want to do that, despite not wanting to boost the threads' half life or add discussion volume.
4chan has a hidden feature to help with this and make the boards a little less spammy: the sage tag. If you wish, you can type "sage" in the options field, and your reply will not bump the topic to the front page as usual. Every forum ought to have a "sage" feature, but LessWrong needs it in particular, to fight a natural trend away from its sometimes dry topics toward high context drama and political discussions.