These issues are all very similar to the difficulties with interaction between JS and C++ in web browsers. A lot of engineering and specification effort has been expended in browsers to improve these problems, on things like WebIDL [1], codegenned bindings[2], JITs that understand some of the behavior of the underlying C++ operations [3] and so forth, but for a game engine where you aren't running potentially malicious code I can see that it would make a lot more sense to just tell people to use C++ rather than expend that effort.