Yeah I think this would be a great idea. If you had the capture ability of sci-hub with the invite ability of quora to get experts to critic papers. Then add on-top of that some simple blog features like top highlight, sharing, subscribe to citation links, and comment/discussion (that matches HN's no counter productive comments/etc).

The large obstacle would be paywalls - like sci-hub; any attractive paper would be illegal to have on the service; if you simply pulled from pre-prints (arxiv; plos pre-print, etc..) you will probably lose academic disciplines that do not value these services (biology primarily comes to mind). On the other hand, CS would probably embrace it as a complement to their conference publishing culture.