The thread's old, but the question remains viable. I carry 4"+ (blade length) knives, preferably ~4.5", anywhere from 6 to 10oz. Always clipped on a belt or a hem of the pants, the knife stays glued to the hip and I've yet to find any issues in EDC, but I do find that a heavier knife assists in cutting as well as stability and control. The reasons, to me, are practical—I find a longer, thicker blade far more versatile and capable in a broader spectrum of tasks than delicate 3" blades, and having broken some tips before, I take comfort in knowing I don't have to worry about damaging a robust blade in harder use. I like 5-5.5" naturally-shaped handles that fill the hand well and allow for a multitude of different grips without getting in the way with hot-spots sticking out, such us sharp choils, ramps and other protrusions. In my experience, even a 4.5" blade can have plenty of tip control as well (depending on design), especially in conjunction with a longer handle helping shift some of the mass to the rear. I do believe that some of these are the reasons the people of older times were using larger and heavier knives and tools in general.