In reality the amount of board which is out of the water at any given time depends upon, amongst other factors the speed of the board and the wave shape. You seem to be suggesting that performance is hindered when the board is able to increase or decrease the wetted surface area in response to rider demands and wave conditions, when clearly that isn't the case.
I noticed a bit of a lag between the shape of the wave and the board's response... the exceptionally long lever forcing the entry rocker down (increasing wetted surface) in spite of the reduced tail area and round rails. My guess is it's due to the extreme weight, and perhaps reduced tail area and accelerated tail rocker? Can increased tail volume make up some of that lag? Your increased entry rocker responds well, however, getting the board back up on plane. It looks to me that at this point, flex is critical.