I'd like a blend of Svbtle and Medium. Svbtle is the perfect blog editor interface, and I like the way it displays code samples. (Medium's lack of support for syntax highlighting without the GitHub Gist widget is a dealbreaker for me.) But Svbtle has no social features or commenting features, and I like those about Medium. I also like the social "highlighter" feature of Medium. One thing I'd add (back) is the ability to write notes in the margin.