>>20
The syntax is fine. Using generics does suck, but it almost always sucks. I haven't seen a language where generics are both easy to read and expressive enough to be really useful.
Compile times are bad. Generics are a major culprit once more, and it's possible to mitigate the problem by isolating generic code in separate libraries, but the compiler should be able to automate this. Doing it manually is a pain in the ass.
Hot reloading functions would be really good for some kinds of development. Rust cannot deliver that at all, but in the future I hope there will be a complementary language that consumes Rust libraries and supports faster iteration for business logic.