Here's a question: Who is going to use this besides the community of developers currently using emscripten, asm.js, and related technologies? Read: game developers. (Also game developers widely don't use these web technologies.)

What I'm afraid of is developers who think they're clever working with WebAssembly to feel like "real developers" shitting up the ecosystem more than it's already polluted. Or some undergrads/Java developers from Google creating another Dartgular but this time claiming that using their new EdgeScript (a real compilable language that utilizes WebAssembly!) is better than just using straight up JavaScript bindings to the existing Web API. Another frankenframework that everyone has to put up with, and will eventually drop support for.