Seeing how JSX is blacklisted in Babel, I'm interested in the project's stance on other non-standard features enabled by transpilers? e.g. Annotations in Traceur, or async/await?
I see the issue with them is you want to use Traceur/Babel only for ES6 module support (makes sense) - so shouldn't they be restricted to just that? Then for other features we can run an additional pass ourselves with all features enabled?
But then, there's the speed issue of having to do the pass twice, so couldn't it just be unrestricted?