That would be an interesting idea. I gather you mean the camera would be on the pencil and the pencil can dock either on the long or short edge of the iPad?A usb-c charging gen 3 pencil could be the answer as to how to move the camera to landscape in the pro model iPads.
It's an interesting idea, but it doesn't seem like a design language that Apple would follow because it's combining a non-pencil function with a pencil and these two functions have no use for the other. I could be wrong, of course I can see other companies attempt this approach but it doesn't seem it would work with Apple's design.
(But then of course, we now have the monstrosity of a 1st gen Apple pencil that comes with a Lighting to USB C dongle just so the iPad Air can be used with it. That, is very un-Apple like because it's ugly, clunky, and is a design compromise in attempts to continue using an older model with an updated system. Absolute YUCK YUCK YUCK!)