Whether on-site or off-site, comments aren’t the right communication vector. Instead, a redesigned, curated section for Letters to the Editor or one step further, Letters to the Author might cultivate a reading community much more effectively than the commenting platforms in use today.
This is a part of what I like about Tumblr’s “Ask” functionality. It’s not that I don’t want to hear from my readers, it’s that typical blog comment systems are a horrible way to facilitate any sort of meaningful discourse. I much prefer to straight-up publish insightful comments sent my way and respond to them as necessary.