Reconfiguring the administrative layout

Describe your issue or idea

I've been thinking about ways to improve the administrative layout for content editors and have made some customized changes that (I feel) improve the experience. It's basically some cobbled together field groups and CSS that help organize the fields I add to a content type, and it works fine, but it got me wondering whether it is the kind of thing that would be useful more widely and whether something like the Administrative Layout page could be used to drag-and-drop fields that had been added to content types or taxonomy vocabs somehow. (Maybe the Layouts system is not the right place, I'm not certain)

For reference, rather than a single column solid list of fields like this:

I am trying to break things up into groups and even a sidebar on larger screens:

For reference, right now I am doing the following:

• Install the Field Group module
• Create field groups and give appropriate classes to each group (e.g. could be a details class on the green sidebar, and a media class on the blue section) for each content type
• Place fields all within the relevant/appropriate group
• Use a subtheme of seven to adjust layout and styles on those field groups (e.g. referencing the classes added above, such as .details)