Having to use functions on built in types like strings.HasSuffix(strings.ToUpper(...)) isn't that bad to me. If I'm chaining a bunch of function calls on a single string, I'll want to separate them on different lines for readability anyway. It'll be creating and destroying a few implicit copies either way, so I have never really felt any pain from that.

Java has no linking, but you have to go through the JVM. Golang produces native binaries. Not really a fair comparison. That being said, my brain is normally a way larger bottle neck than linking time for unit tests.

I'll cede the gripes with enums and error handling (although I hated the way Java exceptions always ended up way too overloaded way more), but I find the typing a really good balance between strong and weak. It's strong enough that you have to be doing something really weird to mess up, but weak enough to be flexible.