You could always use FP languages for FP and leave JS be...
Also, I don't see how "let's not make a thing better just because it was not meant to work this way" is an argument.
I'm sure there is a fallacy name for this, but consider some other examples: "You could always use fridges for cooling and let cars be" or "You could always use computers for browsing the internet and leave phones be".
You could technically use some FPLang-to-JS compiler,
but those suck more often than not.
Features like the function bind syntax are only possible with Babel or another transpiler. It will likely be years before you can use them practically without a transpiler in the browser.
A lot of the new syntax/macros/APIs/etc should just be built as modules or Babel plugins rather than core language features. Just because [Syntax X] improves a couple of code snippets doesn't mean it needs to be shipped with the next version of JavaScript.
I like this idea a lot. Mostly because it would keep JavaScript from becoming the huge syntactical and idiomatic minefield that modern C++ is.
Sure, most JavaScript code is imperative, but there's no particular reason it should be. Functional programming isn't some late addition, either: the language's design was influenced by functional languages alongside imperative ones.