The code that I have to work with is static. It just happens to be JavaScript. Aside from writing some type casts and a linked list implementation, the standard implementation for a project like this doesn't have to be large. And yes, it boils down to a trivial C compiler.

Also, Uglify 2 modifies global properties if you tell it to, and neither uglify nor closure compiler do well with object properties, which can be renamed.

All of these arguments assume that a developer is unaware or not understanding of the mechanisms that their code uses. It seems no one is interested in using anything other than emscripten/LLVM.