> Then there is the whole experience, again depending on the language, to produce a .wasm file, alongside the set of imports/exports for the functions, instead of a plain "-arch=wasm".

Doesn't the "WASM Components Model" kind of solve this? I've been hacking on a WASM-app runner (in Rust) which basically loads tiny apps that are compiled into "Components", and seems simple enough to me to use and produce those.