This is funny timing to me, because just the other week I did a dive into WebAssembly and WASI 0.2 (https://jsdw.me/posts/wasm-components/) and assumed that 0.3 would be a while yet as there was no obvious (to me) sign it would come for a while!
Once the tooling is there and Rust has a wasi 0.3 target I'll give it more of a look at :)