Weird , I posted a show HN yesterday that actually find
constructive "drama" in threads. But the HN title was poorly worded. I changed the copy on the website since, thanks to some early feedback. You can find it here https://news.ycombinator.com/item?id=26298358.
wouldn't that simply be comment_count > N ?
Drama (controversy) may be more like replies per parent.
Flame wars, depth per parent.
Engagement, top level comments per upvote.
If I were designing a heuristic for this, it would be based on a threshold of flagged comments and the existence of more than one post from dang.