We can use zip to our advantage. We do that when we move our whole body to the ball when we use our hands, rather than just reach. When you reach and deflect a ball, it often appears that the keeper is batting the ball. When you get your body to the ball, you keep your hand and forearm set up early so that you can deflect and then get your body there to make the skill. I think your legs are really important when you make hand saves.
Footwork is still critical because it dictates body position.
There's no point in worrying about the skill to use at point A if you can't get there. When you get your body to the ball, you need to get your hand and forearm set up early so that you can deflect the ball, as opposed to batting it. With hand protectors, hard shots have become easy. Too often a ball without pace is more difficult for the keeper. You need to know where the ball is going off of your hands.