Wasm has a fundamental problem: int64 is an insufficient data type for real use cases. If you want to create some kind of plugin system based on Wasm, you need to exchange structured data. But most languages disagree about the memory layout. Dynamic languages do tagging, compiled languages do not. And the UTF issue shows that even with strings, there's still no real agreement.

Furthermore, there are now competing interest groups within the Wasm camp. Wasm originally launched as a web standard: an extension of the JavaScript environment. However, some now want to use Wasm as the basis for replacing containers: an extension of a POSIX environment.