Evolving JS into language with minimal dynamic classes such as Python or Ruby should be easy as all interfaces are already "classical", you just need to add some syntactic sugar. This approach was already proved to work by CoffeeScript and TypeScript. I can't imagine how JS could be evolved into clean prototypal language such Io without breaking backwards compatibility.
There is no hope for JavaScript to become elegant prototypal language because of the design mistakes that were done in the past. All that TC39 / ECMAScript.next committee can do is put even more lipstick on a pig.
http://this-plt-life.tumblr.com/post/36425234595/when-somebo...
http://this-plt-life.tumblr.com/post/41438931672/when-somebo...