Reddit has subreddits and you can choose the ones from which stories appear on the front page. HN can start with allowing users to 'frontpage' other users aka whitelisting by showing stories from only these users on the front page. The next logical step is allowing blacklisting. Version 2.0 of this would allow whitelisting and blacklisting of content-sources (sites), in addition to users, so that I could blacklist certain blogs if I wanted to.
This will result in some fragmentation of the community, but in my opinion, it will keep HN interesting for everyone. This may also reduce the need to answer subjective editorial questions such as - we don't allow politics, but is open-source-politics politics? Is coverage of world-changing-elections allowed?