[sanxiyn]

Null is evil because it forces programmers to constantly check for null when compilers can do that much better. There can be situations when null is handy, but it shouldn't be the default. C++ reference can be used for similar purpose.

Global GC is definitely a language issue. It affects language semantics.

Avoiding shared mutable state does not mean making copies. If you can statically check there is no other reference you can avoid copying. Think advanced move semantics.