I've been looking at the stage 2 and 3 proposals. I have a difficult time finding use for any of them except for Object spread/rest. The stage 4 template string proposal allowing invalid \u and \x sequences seems like a really bad idea to me that would inadvertently introduce programmer errors. I do hope the ECMAScript standardization folks will raise the barrier to entry for many of these questionable new features that create a maintenance burden for browsers and ES tooling and a cognitive burden on programmers. It was possible to understand 100% of ES5. I can't say the same thing for its successors. I think there should be a freeze on new features until all the browser vendors fully implement ES6 import and export.