We definitely want to make it easy and painless for people to give feedback to help improve the documentation. I don't know that Disqus comments is the right way to go about it.
(I can't say I'm thrilled with Disqus in general. Once I integrated Disqus into my website, and ultimately abandoned it.)
Though it would be nice perhaps if there were some way to be able to search GitHub for any open issues against a given documentation page, and have a link to that search available. That would be a little like "browsing a comment section".