Honestly, you lost me here. I am so sick of algorithms trying to serve me what they think I want. I'd much rather be able to just say "Give me X" and get X, not "But also you might enjoy Y". It also seems ripe for abuse further on down the line whenever money begins to be a problem and advertisers are breathing down the site's neck.
Additionally, as long as I'm just giving kneejerk personal opinions, I hate that all these reddit clones are copying the new-reddit "centered" setup with huge amounts of blank space on either side. I think you're right to be inspired by HN, especially when trying to foster more high-quality discussion-oriented content. Emphasize the text, let it take the whole screen!