There is a certain set of languages that the Julia team is experts in. But the world of languages is very diverse and big parts of it are lacking representation, so we miss out on their insights. Eg I think most core devs are experts in C, C++, Matlab, Python, but not as many experts in Haskell, OCaml, Rust, Racket, Common Lisp, Clojure.
I'd like to find ways of attracting those other experts into our community, and making sure we use their insights whenever we can.