Don’t forget to include the basics - upvote, downvote, unvote, comment, submit, save submission, save comment - and have all that sync when reconnecting to internet.
I've been focusing on reading, but it looks like there is interest in writing too. The HN API doesn't support writing, so the username and password has to be stored. It's important that reading keeps working even if HN changes their backend in a way that breaks writing. I'll think about it.