I wonder if it would make sense to provide a new ui element for the basic ui.
It should be configured similar to a group element with some child elements but with different rendering.
There is an icon/label from the group element and at the right hand side a small list with the childs (in a smaller font)
This would save some space especially in small devices.
You can already reach this using a proxy item (not with the layout suggested, but with the Information in the sitemap item).
If you would really like to have the proposed layout, you could always try to write your own front end, you have the rest api waiting for you.