I personally hate mega threads. It fucks with front page algorithms. Sometimes I'm not even aware of large events because I didn't know there was a mega thread on a specific community that you might not see if you're just looking at your front page, depending on how late the mega thread gets to the scene. Or newer articles with additional detail revitalizing the discussion under a new post.
I would rather comb through a couple threads, which tend to have some subtly different angles on the overall discussion.
I don't know if the algorithm has been tuned better, but I have totally missed big events until someone has directly mentioned it to me, because of mega threads. I suspect it may because the initial burst of community participation may happen in the first couple threads, and by the time a mod comes in and either uses an existing one as a mega thread, or starts a new thread, the participation has waned, so minor stories rise above.
I heard, by mouth, that Trump had been shot about an hour after it happened. It was no where on my front page, either "Active" or "Top Six Hours". I had to go to the News community directly to find it.