For Go to be great for systems programming, the unsafe package needs a few more primitives and better control over the GC.
I don't know what this means. I've used Golang successfully for USB drivers, emulators, web and database servers, testing tools, a debugger, and cryptography. It seems evidently suited for systems programming as it stands.
Someone is always going to be out there saying that any language isn't ready for prime time because it lacks feature-X.
But for others aspects that are not related these two(class system, concurrency), I would say they look quite similar.