HTML imports allow you to bundle HTML, CSS, and Script and import them in one step. ES6 only handles the script part. We very much love HTML Imports on the Poly

HTML imports allow you to bundle HTML, CSS, and Script and import them in one step. ES6 only handles the script part. We very much love HTML Imports on the Polymer team and they aren't going anywhere for us. I expect that when the ES6 modules loader spec is finalized it will be fully compatible with the underlying semantics of HTML imports, and they will work quite nicely together.