In the realm of live programming, I also plan to add more extensive support for hot reloading of dynamic libraries.
The compiler-as-a-service (which is also in development and quite unstable) will be made aware of running copies of your application and it will be able to orchestrate the reloading of native code, while collaborating with the user code to persist and restore any world state when this is necessary.
Obviously, the goal here is to get closer to the performance of the final shipping code, because in certain types of software like games, even small drops in performance could make the product much less usable.
When end-user extensibility is required, I think we should strive to develop a framework that makes writing plugins extremely easy (for both parties). Dynamic libraries and native code would make most sense to me here as well.