Autowire seems like a first step towards a framework like Google Web Toolkit, where client and server code can be written in the same language. The questions is then, what can we learn from GWT and what can be done better?
Maybe Java was the reason why GWT never became widespread (being less flexible than Javascript with closures and stuff), but this should have changed with Java 8?
While I think Autowire will be a very useful tool, I'm not seeing how it's "a first step" ... I have successfully written and deployed Scala on both client and server without any issues since some time already.
I think the issue with GWT was that it
a) tried to be a framework (not sure why Java people love to build frameworks instead of libraries ... libraries compose, frameworks don't)
b) and required Java which just isn't flexible enough (syntactically and semantically) to interact with JavaScript in a meaningful way.