To everyone asking about logged-in access and write access: this is just a first release! Where it goes from here will depend, in good iterative fashion, on what people want.
I think part of the angst centers around the bit where the markup is going to change. Lots of apps for HN that scrape the UI rely upon the current site to enable things like voting and other signed-in-only actions, for which there is (currently) no first-class API way to do these things. Even if the endpoints for voting change, getting other information (i.e. which items you voted on, so the vote arrows hide) is still markup-dependent.