It's certainly true that Go doesn't currently support compile-time polymorhpism, and C++ does. In that sense, Go interfaces are not a replacement for C++ templ

It's certainly true that Go doesn't currently support compile-time polymorhpism, and C++ does. In that sense, Go interfaces are not a replacement for C++ templates, as you correctly note. However, compile-time polymorphism is a mixed bag because of how it tends to blow out the icache by generating many copies of similar code. Java does away with it completely, and nobody seems to be protesting. The Linux kernel is written in C, and nobody seems to be protesting that the lack of compile-time polymorphism makes his/her job impossible. Clearly, the decision as to whether to include compile-time polymorphism in a language is something reasonable people can disagree about. With regard to a type system for Lisp: it's been done before. Check out Qi.