Compared to Sonny and Sonny 2, I would increase the strength of Sonny. I view Sonny as an evolving creature, as the first classes of Sonny were simple and pretty weak, Sonny 2 takes it into a larger and more complex fighting. So with Sonny 3 I would reccomend improving Sonny in the certain area the class is (Phycological, for example, would be instinct) and weaken it in the other aspects (say, instinct improves rapidly and has great impact on Sonny´s damage, but strength only improves slightly to Sonny).