Pages Builder
It supports multiple layouts, integrated menus and a variety of page blocks. As an example I've created a sample page "About Dolphins" adding typical blocks. Once other Modules start providing their blocks it would be possible to add comments, members, notes, etc, etc. This is only the foundation - BoonEx and external developers will make it shine!
https://www.youtube.com/watch?v=BAGXHh84ZDw