I feel like Go is a very natural step from Python because it's still pretty easy and fast to start with.

(and if you want to embrace static types, the language starting with them might get advantages over an optional backwards compatible type system)

You may have read this already but the biggest surprise one of the Go creators had was Go was motivated by unhappiness with C++, and they expected to get C++ users, but instead people came from Python and Ruby: https://commandcenter.blogspot.com/2012/06/less-is-exponenti...