If I was the ball, I think I would try to 1. maximise the surface of contact with the ground and 2. maximise the vertical compression so that the release will generate forces that are normal to the ground:
In your example, a lot of the energy stored by the compression is lost: if the released surface does not touch or hit the ground, it'll just move air around.
However, I am also a great fan of Richard Williams's The Animator's Survival Kit, where one of the most valuable lessons is probably to focus more on the viewer's perception than on physical accuracy. Actually your animation may look a lot better if it's not physically accurate.
Here's an example from Williams; see how the 5th frame stretches the ball before touching the ground, for no physical reason:
So, my idea would be to go for the very simple vertical stretch (such as in this video), and add dramatic effects instead, such as causing the ball to shake and vibrate more and more as it squeezes itself. I suggest watching various animation examples frame to frame. There may also be good stuff in One Piece!