I would argue that compiling to asm.js isn't exactly transpilation if the Javascript engine is trained to recognize asm.js and specially execute it, optimizing

I would argue that compiling to asm.js isn't exactly transpilation if the Javascript engine is trained to recognize asm.js and specially execute it, optimizing for speed. What is "3rd class citizen" about that? You can draw to a canvas from C code compiled to asm.js if you desire, or manipulate DOM through a thin layer of JS abstraction, if that's your wish. Sure, it may be clumsy because currently there are no good libraries and frameworks covering those use cases, but you can't blame the technologies for that.