Headless Authoring user experience (HAX) is an attempt to completely replace HTML going for a panels like approach except not panels. Goals of the project include:

• making a completely entity based, drag and drop container to element approach to page layout and building
• ability to build templates through the interface for later reuse
• NOT specific to Drupal or any CMS though it is being engineered around talking to a Drupal 7 based RESTful backend
• ability to convert generated layout to HTML and dump into a body field for expert mode
• stand-alone editor that gets authorization from a CMS / backend
• render capabilities provided by HAX that can then pass rendered output to CMS (leveraging its caching ability yet HAX handling the layout / structural generation CMS agnostic)

See https://haxtheweb.org