I am speculating that most if not all the ipad weight is its battery. when you look at how the air is made and how small the motherboard can get. the ipad should be thinner. the air has specs of a higher heat cpu chip and faster graphics chip yet still wields a thinner case. but at the same time if you examine the air despite being more powerful its slightly larger case size is 99% battery related. I have high hopes of a lighter ipad just like everyone else but given the ipad is likely mostly battery weight like the air I dont see it getting very much lighter without a material change. maybe this is obvious and i didnt see it before?