"the language itself is held hostage by browser vendors, some of whom have shown a strong inclination to not give a fuck about owning up to and fixing their egregious mistakes"
* Destructuring Assignment.
* Splats (Variadic Arguments).
* Lexical "this".
* Array and Object comprehensions.
* Classes (As sugar for prototype wrangling).
* String interpolation.
... to name the bigger ones. Many of these can be found in draft form on the ECMAScript Harmony wiki: http://wiki.ecmascript.org/doku.php?id=strawman:strawman