[jamesmacaulay]

I think people are still figuring out the best ways of structuring large applications in Elm. See for example this discussion on routing from earlier this year:

https://groups.google.com/d/msg/elm-discuss/Hdpn3x0554c/3aFt...

Elm is still young but Evan is doing a great job of pushing the language forward.

If by "efficiency" you meant performance, then this is a good page to read:

http://elm-lang.org/blog/Blazing-Fast-Html.elm