Google is not going to try and advance Java development. They should just deprecate it and switch to Go. But right now they seem stuck in the middle, not doing either.
That would be a step backward, we really need generics and a reasonable support for exceptions on Android (or any large scale system, for that matter).
Go is a fine language at the system level or to replace Ruby/Python scripts but that's about it.
My beef with Go is weak web-programming and prototyping support and immature libraries. I'm surprised there's been so much uptake in the Ruby/Python communities, which are very strong in those areas, but I guess Ruby/Python are now being used outside their original domains and those use-cases are pretty ripe for a language like Go.