My question is really why not choose something really higher level ? Go is like stuck in the middle. If I need very low level, I'd choose rust. If I need high level, I'd choose Python. Go is kinda filling a weird niche between the two and I rarely find a case where I feel like it's the best choice.

Anything that is robust, dynamic, with a big ecosystem. Python, Ruby, whatever have you. You don't need raw speed since the OS API does most of the work, and the ease of programming would make it more productive. In the end, they added Python anyway for stuff like "compose", so I'm missing the point of using Go for this. The Go code is not even network bound, the ability to get multicore easily is not a bit advantage here since you spawn a new process anyway, so really, why ?

OCaml is my first thought in that space.