* Interfaces which can have fields would be really, really great.

* A rust-style borrow checker would make dealing with channels and pointers a lot safer.

* Equality operations for slices would clean up some ugly parts of the standard net library (addresses are []byte, so a direct x == y doesn't work but seems like it should).

* Closed enum sets: some ability to setup an enum type which can be "complete" when used in a switch statement without needing a "default" and which will only panic/fail when a bad type conversion is made. Let me sanitize out a whole bunch of possible errors at one point in my code when I want to use constants (and be warned when I break the guarantees).