Stackoverflow seems to me to be a giant case of post hoc ergo propter hoc. "We made a site driven by points and numbers and rules and gamification and it was success, therefore it was the numbers and gamification that did it". No, SO was a success because the tech world was gasping for a forum that wasn't a) mailing lists or b) expertsexchange. That's all. That's why the majority of their non-tech sites have bombed.
If Discourse is a success it will be because phpBB is hideous, not because of any merits shown here. A better model to ape would have been the truly successful community sites -- think the Well, or Metafilter. Flat. UI that gets out the way.
Humans are superb at managing conversations, tracking threads and managing state. It's how forums manage to be so good despite phpBB and the like. Let the humans get on with it. Get out the way.