Rust needs a good set of “batteries included” stable libraries and some easy way for people to find them. This might require serde and some form of specialization to work on stable.
Rust’s type system is really missing integer generics, through we don’t know the implications of it. Looks realistic for EOY 2017.
Our tools team needs to have more people than just @alexcrichton (with @petrochenkov and @jseyfried cleaning up our frontend, our compiler is starting to look fairly well - great work! We need something like that but for rustdoc and our metadata loader). Get the FFI story done with!