WebAssembly is still work in progress, isn't it? There are proposals to have 2 text formats: low level one (Asm.js like) and more high level representation [1]. So, I'm dead sure the way out will be found. If not, community will create workaround-ish solutions in a form of "WASM -> language of your choice" decompilers.
[1]: https://github.com/WebAssembly/design/pull/457