Hopefully a user of C# will chime in -- I've spent very little time with it, and only recently evaluated C#'s extension mechanism for the purpose of comparing it against other language's implementations.

That said, elegant and concise syntax does not require eschewing an internally consistent, fully specified type system -- the two are not incompatible, as demonstrated (subjectively) -- by many existing FP languages. I argue that elegance/conciseness requires either FP language features and advanced type system, or abandonment of rigorous typing.