the rocker seems to corespond to the amount of v in the hull. the 16 with the v type hull is for sailing in the surf and seems to need all that rocker to do the job it does. you will find the 18 has more rocker than the faster course racing cats. the 18 being shaped by a surfer to be sailed in the surf, but with daggerboards and a rounder bottom shape.
the flat bottomed spinaker boats seem to have pretty flat rocker forward with a rocker knuckle aft, which in a way seems backward, but it seems to work for them. not enough rocker and the boat seems to stick to the water or go slow for some other reason. sol cat rocker is the example there.
btw i've sailed with 3 on a 16 many times, most teenagers but not always. i've also solo'd one in wind strong enough to not need the righting line whilst righting. just had to pull on the dolphin striker a touch, then dive for the new windward hull to keep her from capsizing the other way.
bottom line: wings on a TheMightyHobie18 allow a family to cruise the lake in comfort and style.