There is also dte[1]. It hits exactly the same notch and offers an extremely lean editor with Unicode support, CUA key bindings and much more. It has replaced nano as my terminal editor.
You realize that you're asking this in a discussion of a tool that is intended to be installed out of the box on Microsoft Windows, where vi is not installed out of the box, right? Your "everywhere" doesn't include the primary use case for what is being headlined here.