The control panel makes it really hard to do anything if you have a case. It is not an HP TouchPad, there is no sensor in the base below the screen, so why is the swipe feature all the way at the bottom? And why do we have to depend on that for all the main controls?
Whether you like it or not, Apple's devices aren't specifically designed to be used with cases. Apple designs the OS for the devices (and vice versa). Case manufacturers have to design around this to have minimal impact on usability.