A curved handle is ideally suited to duelling purposes allowing quick twists and other neat moves. You would normally expect to see it on certain sorts of fencing swords.
Less good for a power fighting (which, ironically, is what real-life sabre fighting is), but with a lightsabre you don't need any strength behind your blow at all.
Well, it;s all to do with the way you hold a fencing sword. The two main grips are the French Grip, which is a bent grip like Dooku;s, or a pistol grip which looks... pretty much like a pistol handle.
Both of the involve you gripping the sword in an entirely different way to a medoieval longsword- more like how you would hold a gun. Far more flexible.