The idea is have a Transform Cage to move, rotate and scale in the 3D viewport (similar to the gizmo that exists for 2D UV editing).
This is will be realy useful for Grease Pencil and 2D animation workflow and is common in other 2D animation programs.
Please, check this video for more info:
Daniel
This works for a 2D only cage, however the 3D cage works a little differently.
Could you update the design with an example of how this cage will work when viewed from an angle?
One solution could be that In front/side/top/etc views only show one rotate handle
and in the perspective show the all 3 rotation handles
Another aproach is this from Maya, that don´t take acount the center pivot point
Perhaps it is a bit overloaded, but the box transformer could be used to SCALE and SHEAR, and pressing the Alt key, to MOVE and ROTATE.
Here I leave a capture of the two modes, the yellow shapes allow to scale and rotate from the opposite base, and the RGB move and Shear, depending on the mode.
Starting from the base of the first image, I made a small update.
Understanding that the pivot is always in the opposite corner of the active grip, I have colored them depending on the number of axes of influence. The black box has nothing assigned since I don't know if it's worth it based on the central pivot or with respect to the view.
I considered what Gizmo should look like, when the selection was small, and I have also tried to overload less.
