Is that it just doesn't matter very much. F# has very powerful generics, and there are particular circumstances where that saves me a lot of typing. But you can still get it done in C# with less powerful generics, or Go with none.
F# has sum types, and replaces null with an option type - great ideas, but you can approximate these ideas in any language if you need to.
Similarly, Nim's metaprogramming has let me do some really clever things, but again, it just saves some typing.
I've found that language features and properties are often given more weight than they deserve. The really hard problems I've had when coding are just the actual problems. And while a particular language can be life-changing in particular problem domains, its rare that they are life changing in general.
Go is maybe the language I think is least interesting of all of the ones I've played with but I currently prefer it over the others because
1. stable, mature language and tools (unlike nim) 2. fast compile times (unlike rust) 3. compiles to native executables
F# might be my favorite if it had fast compile times and native compilation. Rust might be my favorite if I ever grok the borrow checker. But if someone said I had to use language X to do project Y I would almost always be fine with it, unless there were insurmountable performance problems caused by the language.