The "cutting-edge" web frameworks that already exist today are the fat client frameworks you describe (client-side rendering). The web frameworks of the future

The "cutting-edge" web frameworks that already exist today are the fat client frameworks you describe (client-side rendering). The web frameworks of the future will have robust server-side and client-side rendering, in my opinion. We're already seeing a little bit of this with Airbnb and Rendr for Backbone, React, and Twitter's web app, but it's not quite there.