I really like the simplistic principles http://roca-style.org defines for web applications.
I find single page applications way too complex. The amount of code duplication is horrific. So everyone ends up building platforms like GWT or Dart in order to hide that overhead. But that does not mean that things get simple.
I can see where you're coming from but I find that React (with node on the server and a RESTful database) eliminates a lot of the code duplication because I can run the same view rendering logic on the client and the server.
ROCA is an appealing idea, but my concern is that in order for the the-API-is-the-web-client approach (which ROCA as I understand it seems to advocate) to work you end up mixing two entirely separate levels of abstraction: what may be a good abstraction on the API level may not be a good abstraction on the UI level. It's sufficient if your web app is just an API explorer, but not every app lends itself to that.
You could say that then we shouldn't be building those apps, but that's simply not realistic.
I find single page applications way too complex. The amount of code duplication is horrific. So everyone ends up building platforms like GWT or Dart in order to hide that overhead. But that does not mean that things get simple.
(Maybe I'm getting old.)