Just because something is familiar doesn't mean it's not worth exploring. Often seemingly familiar things are misunderstood because we don't take the time to understand them.
> ...what things make the HN ecosystem more rich and complex vs. what things make it dumber...
I think "flamewar" avoidance leaves HN a little flat, actually. There is a lot rich and complex in giving the usual tech/SV crowd a challenge to its viewpoint from time to time. The goal isn't always changing minds or learning new things. Sometimes it's just to realize that smart people can disagree with us, and because of that, we need to respect people that disagree with us.
Maybe we need to let passionate, smart people have it out from time to time so everyone can be reminded which positions can stand up to the flames just fine. Otherwise, we forget that the farces of "them" that we enjoy are just farces, not reality. And that makes us dumber. And boring. And intellectually stale.