It's a great idea! I think a site like the Washington Post would need to be financially incentivised though. Currently sites can earn money from Disqus because sponsored links are included within the Disqus widget, and the publisher earns a cut from those. With what you're proposing I think only the commenters would be rewarded, not the article publisher. Maybe if the publisher also published the article to Steem, either the full article or an except, and then some how that and the comments were linked. Then the article could gather rewards and those would go to the publisher, meanwhile the commenters reward each other and build community around the news site.