And I ask again what that is supposed to mean in technical terms, and what specific problems would be prevented if Go's type system was "more expressive".

> They're preferred

I am fully aware that for every given language feature, there are people who prefer that feature. And many languages reacted to that by including everything and the kitchen sink. That made many languages very "expressive", but that expressiveness comes at a cost: It also made the languages themselves become bigger and more complex.

Go isn't about having as many features as possible though. Quite the opposite, it's about having as many features as necessary, and as few as possible. Why? Because it keeps the language small and easy to learn and the code easy to read and maintain.

And to me (and judging by the sucess of Go I am not alone in this), that is a lot more important than a bit more "expressiveness" in things that one may come across every now and then.