ES6 may well be the death of Javascript. They've managed to turn Javascript into Java, which means web programming is about to turn into a buggy nightmare.
Java is usually criticized for adding features too slowly and promoting bloated codebases due to an inflexible language. I don't see how this is anything like Javascript or promotes buggy programs.
Tooling ES6 code is more complicated, learning the language is much more complicated (it was nicely minimalist compared to other mainstream languages). At least they mostly stuck to mucking with the syntax--saying they turned it into Java is crazy until they introduce Java's broken threading.