I think it's useful to differentiate between JavaScript the classic language for adding limited interactive behaviours to otherwise static Web pages and JavaScr

I think it's useful to differentiate between JavaScript the classic language for adding limited interactive behaviours to otherwise static Web pages and JavaScript the language for full-blown MVw web apps and JavaScript the ubiquitous portable script language. For the first and third use case, really not much has changed since ES3/ES5: if you want portable JavaScript and appreciate simple "press reload button" workflows without babel or other complex transpilation steps, then ES6+ features don't add any essential capability, and I tend to avoid them. If OTOH you really need to develop SPAs with massive code bases and third-party libs, then ES6 and in particular ES7 with async/await is a big win. But I can't help wondering if the tension between these language profiles is going to work well for JavaScript in the long run. IMHO for full-blown apps there are much better alternative back-end languages available, and in any massive ES6 code base I've come across the desire to introduce types and type metadata is very much noticable (Angular and Typescript come to mind).