Sure, no language is perfect but some things in Go were apparently "to make it simpler", but by lack of them it made the code in the end more complex and/or verbose.

Lack of generics made a lot of code less type-safe than it should, and just more complexity and/or duplication.

Lack of sum types made some types ugly (like mentioned IP type), and other ways of control flow harder. Rust-like Result<T> would be massive improvement to verboseness of error handling in Go for example, without really any drawbacks.

That doesn't mean there nothing to be learned from mistakes previous languages made and striving to create iteratively better languages