I think this is a really wise take, and one that I honestly haven't seen before. I would certainly try a language like this.

The one thing I would add: Provide a well-trodden path to easily drop down into Rust/C/C++ for performance critical functionality. I have found this to be a big point in Python's favor over Go; you can write things the slow way (ie. executing in the Python runtime), then profile and figure out where to push things down into an extension. Often you're doing something that already exists in a library like numpy or pandas or polars, but if needed, you can write your own extension.

Does WASM enable FFI on its own?