I would like the same for hacker news e.g. if patio11 adds the 1000th comment in a thread, I want to see it. Perhaps even individually ranked: opt in to get a clintside ordering of a discussion that uses my own up and down votes to help re-rank the comments.
Stackoverflow is frustrating because experts get much the same influence as ignorants. I am forced to read every answer and comment to find the information gold (the ranking helps, but it doesn't help enough). Best answers almost invariably are written badly and don't cover corner cases (possibly it is because I usually have to find JavaScript answers, or because JavaScript is hard to write well).
But if a question gets a lot of new answers without the original answerer reacting any more, just change the algorithm to show the answer with the most votes in the pas month/year.
This is a problem which should be solved.
One of the problems StackOverflow is facing due to its age is that what was (correctly) accepted as the best answer 5 years ago isn't always the best answer today. For some questions, the better answer has more upvotes, and this reflects that.
I kind of wish StackOverflow had something like "Order by most votes in the past year" or "Order by most recent 50% of votes" or something, as it would probably be more accurate, but I get that it's complex both technically and from a UX perspective.