Now that the language syntax is mostly stabilized, i am hoping that more focus will go to the standard library. Currently it seems rather ad hoc and not always consistent (which is understandable because of all the language changes).
I dont know if that exists allready but I think I am going to implment a persisten vector (like clojure vector) in rust and see if it interacts nice with other libs.
I have done with other languages, would give a lot of inside into rust.