Ability for plugins to create new views where the plugin is responsible for all of the rendering

 I've been looking though the forums, but as far as I can tell the current plugin APIs only allow you to manipulate text-buffer views. Is it possible, or is it planned, to introduce the ability to create new views where the plugin is responsible for all of the rendering? Like an empty container, where the plugin author can use the UI toolkit of their choice (with the appropriate python bindings), to build eg:

- Markdown preview pane
- Build/CI status overview
- Threads/callstack for a debugger plugin

etc.

Or alternatively, to allow the plugin to create web views, where the UI is in HTML/CSS/JS, and where the ui can make callbacks to the plugin code through a mechanism like postMessage.