Have you actually used Typescript? It's definitely better than Python, and I'd personally prefer it to Haskell / Livescript. I would love to hear what people actually think the "flaws" are with ES6 Javascript and Typescript, because they have been disappearing fast over the past two years.

WebAssembly will be great, but as a complement to Typescript, not as a replacement. I would love to import a native module for the small chunk of my code that needs to do heavy lifting. And I don't see any reason why the Typescript team couldn't eventually build a WebAssembly compatibility layer.