the only way for mozilla to address string/DOM manipulation would be through language extensions (in which case they lose the "its just js" selling point), or craft their rendering engine to special case what is recognized as asm.js output (possible, but would bloat the rendering engine and create weird bugs)
the v8 folks keep telling people that further optimization of js runtimes is limited due to the nature of the js language...but mozilla can't look at alternatives without giving the appearance of losing their independence
