This is the only approach that works across a wide variety of languages, and yet I can't help but think that would be a terribly bad idea in terms of user exper

This is the only approach that works across a wide variety of languages, and yet I can't help but think that would be a terribly bad idea in terms of user experience. Because you would end up with major apps written in Ruby or Python, draining batteries and stealing all your RAM. Not that we aren't already headed there with a ton of app frameworks embracing javascript.