I don't get why the miniview port has to be so limited in size. If anything you should just allow a second viewport that can be any size so you can manipulate objects, while seeing whats going on in the camera view clearly, and also allow the switch camera to be shown on this viewport.

Or maybe somehow figure out a way to rotate/translate things that are cropped out of the camera view. Jumping cameras is by far the biggest timesuck in 3d animation