What specifically looks bad there? The only decision I see is that string handling doesn't need to be in the language and that it should be a concern of the standard library. That doesn't seem unreasonable to me. Or at least, not as unreasonable as you make it sound. It's true that Rust and Go have language level support for Unicode strings, but the actual language features for it are quite light. It buys a little bit of convenience maybe. But the vast majority of the burden of those string types is carried by the standard library.
