Fewer rollers also means fatter/wider wheels, assuming diameter and angle stay constant. The rollers have to be longer to cover a sector of the wheel, and since they're at a 45 deg angle, that means they'll stick out farther to the sides as well.
Also, can everyone in the thread agree that the Mecanum vs. 6WD discussions were already done this season in
numerous other threads? If someone thinks that horse isn't dead enough, I implore them to revive one of those threads or at least give us a break until next season.