Rocker shape is an important balancing act.....
Too little and the nose of the boat plows into the water like a squirt boat. Great for tricks, but difficult for running rivers. Too much rocker and the bow stays nicely on top of the surface, but cartwheels tend to be very difficult and low-angle.
Also, too much rocker in the wrong place can make the boat push water instead of letting it slide around the hull nicely, thus making a very slow boat that is a bit unpredictable.
The trick is to make the rocker "progressive" so that the water slides under the boat smoothly without creating much pressure on the bow. A river runner should have a smooth transition and not be a butt bouncer like some freestyle boats. The idea is to have available speed and lots of predictability.
above you can see how the rocker has been adjusted in steps on the second Huracan prototype to allow a smooth transition as well as quick resurfacing.