That's already several years late. It was supposed to be ready around 2008 -- then it was cancelled, gone nowhere, and we had to wait another 5 years for ES6 which is still not here. I mean: "This year or early next year"? Add the sweet time the browser vendors will take, browser adoption etc, and it will be 2018 or 2020 when we can use it for mainstream sites.

Not to mention that the "browsers don't really have a choice but to implement it" does not hold at all. Safari, IE and Chrome can continue to ignore it or implement only little parts of it for the next 2-3 years.