The javscript version of the hedonic treadmill ensures there will always be a juicy new feature that node/browsers don't have yet but Babel/other transpilers usually will. Just because it's 93% of the way there on ES6 at this moment doesn't mean that a few months from now people, your team included, won't be clamoring to be able to write with the new sweet features from ECMAScript 2017 or whatever. The only solution is to keep Babel a part of your stack perpetually and really that's not so bad in my opinion.
Remember that performance with Babel transpiled code is still sometimes faster (in some cases, substantially so) than the native ES6 implementations, as optimizing continues on V8's end.
And be sensible about how much transpilation you want, you can use newer presets that don't need to transform the code as much, while still having the ability to layer in newer features (async/await, ES7, etc).
