CoffeeScript proved to a lot of people how much more enjoyable JS could be with some of the lessons in language ergonomics learned from Python and Ruby. I think that ES6 really reflects this. With some of the long awaited improvements, like better lambdas, generators, Set/Map, assignment sugar, better metaprogramming of objects, and standard-blessed implementations promises and classes, I think that JS is finally close to being able to compete in the multi-paradigm space. Sweet.js (or some other macro layer) will also really help in letting people develop new syntactic abstractions for domain-specific stuff. It'll be interesting to see how it all develops.