This was my first reaction as well. I've tried using React but the designer in me hated having views inside my controllers. So I've ended up writing vanilla js, and a helper MVC framework: https://github.com/techlayer/espresso.js which borrows a bunch of concepts from React but is really just a tiny helper lib.
Sounds like React. WCs templates aren't programmable that's a DSL that is specific to Polymer.