Reference types technically already allow for calling directly into the browser APIs as reference types allow wasm to pass JavaScript objects around. So if you import all the relevant web apis, you don't really need any (almost any?) intermediate JS anymore, because you can just forward the JS objects between the individual API calls.
The only real need for JS would be to initialize the wasm module in the first place.
>you don't really need any (almost any?) intermediate JS anymore
I don't think that's true. You still need JS glue code that would return these externrefs. A WebAssembly module loaded through ESM integration can't as far as the current proposals access Web-APIs on its own. As far as I understand there is also a number performance issues related to the wasm spec itself that limit possible optimizations, making wasm second class to JS in terms of performance of WebAPI access.
The only real need for JS would be to initialize the wasm module in the first place.