Polymer 3.0 is pretty exciting! R.I.P. HTML Imports.
Paper elements were automatically converted to ES Modules… except for the deprecated neon-animation, which is a dependency of paper-dialog and some others. Hopefully this will be solved soon. micro-panel is a heavy user of paper-dialog! :D
Also, a new interesting thing by the Polymer team is lit-html, which is not yet actually integrated with Polymer…