There are a few things we need to do like a upgrade tool and some other things that haven't been addressed like how library/module authors should publish to npm (do you include/exclude polyfills, do you compile down to ES5 or start introducing ES6+ code under a different folder or package.json string like "module" or "es2015" which will be out of date, etc)
Also didn't write much about the Typescript support yet but we want to help people use that too if that helps with their development