PM for Go Cloud here (and poster of the Azure feature request).
"Unplanned" on the issue tracker just means we haven't assigned it to a sprint milestone for the team yet.
Azure and more clouds are very much in the works. As an open project, there are many approaches and we're open to all of them.
One other point: since Go interfaces are implicitly fulfilled, anyone can write and share implementations of Go Cloud for new providers or custom services without asking anyone for permission. If you take a look at the implementations we've provided, you'll find it's actually rather easy.