I think if they added curvatures it would make the multi-touch gestures hard to use. Hard to do a 3-finger swipe on a curved surface because your fingers would still need to be at an angle to the surface causing you to unnaturally bend your hand upward.
Try to use a touch pad that is at a 45 degree angle away from you, you'll find your wrist straining over. I'm sure they tried a curved mouse, but then realized the touch gestures would be too painful on the wrist.
Try to use a touch pad that is at a 45 degree angle away from you, you'll find your wrist straining over. I'm sure they tried a curved mouse, but then realized the touch gestures would be too painful on the wrist.