Not all are larger, it's mostly the look of the new short nosed 1000 cbr's. 600's are smaller, lighter and more nimble, also use less fluid capacities and have a thinner rear tire.
The larger crank/wheels/tires/rotors create more centrifugal force making the bike harder to change direction. It's not so much how much weight but where it is.But how can a 1000 that only weighs 20 lbs more than a 600 be worse in handling??? ????