One of the problems with this approach, that I'm not seeing anyone mention in a cursory scan of the existing comments, is that it would make the front page different for different people. Other sites work that way (notably Reddit), but AFAIK, the HN front page is the same for everyone who views it at the same time (possibly modulo showdead; does that affect posts?). This is a useful property to preserve, and one that this proposal explicitly breaks.