It's not just rocker (or not); it's a bunch of different factors and the extent to which those factors affect performance, the degree of effect may vary.
For me, the 188 S7s were easier to manuver/faster in bumps than my 183 gotamas (2007, white model). Perhaps it was due to the short cambered section, tighter TR, or tip/tial rise. Very fun ski; more fun than my Gotamas, except at high speed.
For me, the 188 4FRNT CRJs (118 waist) were tougher than 183 Gotamas, despite tip/tail rise and short cambered section, and I felt this was almost exclusively due to the forward mount recommended by 4FRNT. I believe in a 180 and/or with about a -3.5 mount, they would have been pretty close. Liked this ski better than the S7; far better at speed, pretty close everywhere else except for the aforementioned mount issue.
For me, the 183 Gotamas are easier in bumps than a boatload of stiffer race carver/wide carvers/skinny midfats (70-82 waist) I've skied over the years, like Elan M666 (177s and 184s), Volkl AC50 (170s and 177s), Volkl AX3 (177s and 184s), Volkl Superspeed (175s). I felt this was so due to softer flex and twin tips' ability to skid. I feel this would be the case in hard bumps as well as soft bumps.
Skiing with friends, who are roughly similar ability, I did not feel like my bump or hard snow skiing suffered in comparison, while they were on skis like Dynastar 8000s, Volkl Mantras, Dynastar Contacts (68 or 72 mm), etc.
The foregoing conclusions were drawn over the course of over 60 ski days, while skiing mostly soft snow (25-30% hardpack days) at Squaw, Aspen/Highlands, Big Sky, and Park City/Deer Valley. But, some of them would still hold on harder snow.