Of all the developers I know that I went to university with a few years ago all with just a few exceptions have moved on from vanilla-js to compile-to-JS languages by now (Dart, Clojure, CoffeeScript, TypeScript, …) and the others are on the fence.
What we need is for JavaScript to become a better compilation target and for even more language innovation. Dart is the most ambitious compile-to-JS option. Take a look at Dart's stdlib, packages and support in IntelliJ.
The better dart2js gets (it is really good by now but I can't wait to see how more focus on it will take it further) the more scenarios where Dart can be used in. Just think about all the places that come with a JavaScript runtime nowadays.
Just think of how the JVM allows people to write Lisp/Clojure in enterprise settings. Having a better and better dart2js story allows people to use the tools they prefer without hitting a bureaucratic wall ("compiles to js? fine.").