If you cut out the seats, attach a trailer hook up, put up a sheet behind the driver, and lower the engine, then you've created a truck out of a bus. There was no reason to turn a bus into a cargo truck and the result isn't better than any existing cargo truck, but your transformation altered what the original vehicle is likely to be used for.

Removing the limitations that make WASM such a safe system to implement and replacing it with POSIX system calls is like ripping out the seats and replacing them with a trailer hook up. There's nothing wrong with being able to attach large trailers to your vehicle, but the type of vehicle you're converting may be better off without your alterations.

The JVM contains instructions such as instanceof and various ways to invoke a method that mirror the OOP approach of Java. Garbage collection instructions are also extensively used, of course, but they're not as OOP specific.

Unlike WASI, WASIX adds open()/read()/write()/close() to WASI. It also adds fork(), exec(), and wait(). With modern web APIs (such as the filesystem API) many of these can be added without any virtual implementations, but WASI and WASIX are also targetting other use cases. One use case being pushed by a lot of WASM companies is for WASM to replace Docker containers in a Kubernetes cluster, for example.