I’m not sure if those who read from .profile are expanding shell-calls. Therefore I’d be carefull.
Probably it wont change that often, and also expanding this to early might change with a GOPATH you set manually in a later step of creating your environment.
As I use those tools from the terminal only, I put export PATH=$(go env GOPATH)/bin:$PATH in my ~/.zshrc and I am happy with it.
For anything I want to use more globally I write a PKGBUILD anyway (or use one from the AUR).