On security, I'm not sure I agree. Part of achieving optimizations is making enough assumptions to perform them, and that leaves you open to holes in your valid

On security, I'm not sure I agree. Part of achieving optimizations is making enough assumptions to perform them, and that leaves you open to holes in your validator. If validation isn't correct, then you could potentially trigger the optimizer to create bad code that would be exploitable. We've basically moved to Java bytecode verification to asm.js verification. This is just speculation, but I'm actually concerned about the potential security implications.