Probably keep the same design or maybe the curved rear edge. The increase in screen size with less bezel all around with a camera cut out like the MacBook Pro. Every new gen Apple product with a screen has a cut out to increase the size, except the iPad.
Increasing the actual physical size just to have a 13" will disrupt manufacturing and esp accessories.
Whoever said they need 2 of the same camera has no clue. A product have a redundant feature is plain stupid.
The camera will stay the same and Apple Pencil. If they move the front facing camera on the top of landscape, then the Apple Pencil will have to move to the left of the iPad Pro, but can't bc of the speakers and Obviously can't on the right bc of the USB C Port. So again, placement of AP and Front Facing Camera will stay the same.
I am waiting on a 15" iPad Pro though.