I wrote this analysis [1] in the context of Julia vs. C++ about why I think that Go has not been successful as a C++ replacement. The primary issues are performance (the ability to trade off abstraction for performance, really), generics, and operator overloading. We did not intend for Julia to be a C++ replacement, but it turns out that it's quite a good one and a lot of adopters have come from C++ – I think that these features are why.

[1] https://groups.google.com/forum/#!msg/julia-users/-SGWPUBJKq...