The PWA stack really excites me. Service Workers and the like take the "extensible web" approach, which, for me, gets us back to thinking about a progressive web (rather than relying on JavaScript up front).
I'm also seeing ES6 land in a lot more environments which is letting me start to adopt more of the ES6 sugar because I've always preferred my workflow to be "build-free" (and obviously I then need to build to push to production).
Overall: it's looking good! (...I think)