I hope I'm not the only one, but I really do feel lazily loading javascripts is an overkill and not worth it in 99% of cases.

Even if your concatenated .js file ends up being huge, well, you can set expires headers for a year, and then asynchronously load it on the login/landing page. By the time a user will log in, they will already have the js loaded and ready to fire - not affecting performance in any way.

Unless I'm missing something?