An older editor that I thought was amazing was Acme (http://en.wikipedia.org/wiki/Acme_%28text_editor%29) -- the famous plan 9 editor. http://youtu.be/dP1xVpMPn8M is a Tour of Acme, some really cool features are built into it. Any text is a command.
The problem with this is that it's really, really hard to build a good editor, and when you concentrate on some novel idea the "basic" functionality suffers.
For example, both Vim and Emacs have easily accessed commands for moving cursor by words, sentences, paragraphs and moving to the nearest given character (on top of traditional beginning and end of line, of course). Also for selecting them, copying and pasting, indenting, surrounding and so on, all in 2 to 3 keystrokes. Another example is the multilevel, tree-like, infinite undo of both editors. And many more: mark ring, multilevel "clipboard", registers, very easy to access macros, narrow to region (this one could be Emacs specific, but I doubt there's no Vim plugin for this), search (both literal and regex) and replace (both literal and with expression, incredibly powerful) and so on and on, and that's just built-in purely editing features, not going into integration with other tools or plugins.
I would have migrated to LightTable long ago if it provided at least some of a more advanced, but purely editing oriented features. It doesn't yet, and it will take it long years to get there because of sheer size of a required featureset. And that's still not counting my 3k lines of personal Elisp and some 20k lines of Elisp in installed plugins.
I'm going to give Leo a try, but even if it really is as good as it's web page says I can't see myself migrating to it in the near future. I may use it from time to time for specific tasks, but my daily editing will be done in Emacs; in the worst case I will have to copy&paste bits of text between Emacs and Leo windows if Leo's editing model/core editing functionality sucks enough (I did this with some other editors and I despite copy&paste overhead I was still faster than I'd be staying in the single editor).
Leo is the best implementation of the literate programming method that I've come across to date, and the first time when it all clicked for me.
If this existed, we could start building on that widget and have a decent, extensible text editor from the outset, then build on that.