I would say no. Overall it's an improvement and adds certain sorely lacking features and data types, but the new version also added quite a bit of sugar as well. I've tried to list some of my main gripes below.
Sometimes overloading semantics of characters leads to weirdness. Consider something simple like this:
const onClick = () => ({ ... }); // Note the braces as I'm returning an object
There are little details like that to remember that feel confusing the first time you encounter them.
Even though it's a better language, there's still some weirdness to it. Given I prefer functional style, my biggest gripe has to do with data types. JavaScript is still lacking proper data types that were immutable out of the box. You can use the existing types in an immutable manner if you are careful, but I feel it would be better if you didn't have to.
I know solutions like seamless-immutable an help to deal with this, but it's still a little uncomfortable and you lose out on benefits like structural sharing unless you are using Immutable.js. Then you end up with a far heavier solution and a new API to remember.
Even though JavaScript typing is great for prototyping, it begins to hurt you when you want to solidify your code. I believe it would benefit from a stronger type system or some kind of a compromise that would allow you to give the system some hints at least. Types are valuable information to me as a library/component author and I would prefer a hard failures fast than silent failures for my users to debug.
There's a lot of interest in typing as evidenced by the rise of solutions such as TypeScript and Flow. Maybe we'll see the same as with CoffeeScript and the standard will absorb the best ideas given enough time.
I think they took a nice step forward with ES6, but there's still work left to do. Actually instead of seeing more features I would love it if they started taking features away while solidifying the design. Dropping some old ideas, like defaulting to global variables by default, would be welcome as well. I know linters can do some of the related work, but standard is always the standard.