There's nothing in the HN UI that I've yet noticed that shows when a comment is upvoted (or downvoted) beyond the fake internet points counter next to my username

Up/down votes are irrelevant, though, in this context: if I've asked a question, I shouldn't have to go hunting to find out if people replied (or if they've asked something back, etc)

I don't write so many comments so I can always keep track of everything. Also, HN creates contextual threads for comments, the ones involving you, and I haven't had any bad UX to report so far. The system in its current form works.