[flossly]

Go only provides one concurrency paradigm. Rust support many (if not all).

The type system of Go is very weak. I'd say that'd be my main reason to pass on Go, even when the concurrency paradigm fits the project perfectly.

[jen20]

The biggest reason to pass on Go right now (if your software can tolerate a runtime) is the lack of algebraic data types when doing interesting domain modeling. It makes such a huge difference it’s worth tolerating the pain points of Rust (or Swift, or F#) just to have them.