Sam here from Discourse, I use Discourse to drive commenting on my blog and I love it, ever since I did it comment quality has gone way up. eg: http://samsaffron.com/archive/2013/11/22/demystifying-the-ru... , one could build a plugin that gives parity with disqus, its just a space we have not really decided to enter
Turns out that the extra click required and registration weeds out a lot of the problem comments.
I also find that giving people space, proper preview and excellent followup makes a world of difference (Discourse has reply by email, notifications and so on)
Originally I was considering adding a traditional, add anon comment box, but I am not really that motivated to do so.
