Nice work with this!
A little idea for non-umbrella apps, what if the web folder was moved up one level to be placed directly into lib and renamed into myapp_web. That would bring it little bit closer to the folder structure of umbrella apps.
lib
└── site
├── application.ex
├── blog
│ ├── author.ex
│ └── blog.ex
├── repo.ex
└── web
├── channels
│ └── user_socket.ex
├── controllers
│ ├── author_controller.ex
│ └── page_controller.ex
lib
├── site
│ ├── application.ex
│ ├── blog
│ │ ├── author.ex
│ │ └── blog.ex
│ └── repo.ex
└── site_web
├── channels
│ └── user_socket.ex
├── controllers
│ ├── author_controller.ex
│ └── page_controller.ex
