Will Go Decide the Winner of the JavaScript Framework Wars?

Go's actually a pretty good choice for servers if you go the single-page webapp or native app setup. The biggest weakness for Go, in my experience, is that its facilities for templating, generation of HTML, and webapp development are pretty weak. But if you go the single-page app system, then your server just needs to serve JSON, and Go's JSON encoder is a pretty nice piece of software.

The big monkey wrench in this picture is Polymer, which has significantly more support within Google than Angular and has the advantage of aligning with the emerging web standards that will be baked into browsers. Polymer is still HTML-based, which means that Go still doesn't have great support for working with it.