First off: I really like Jiggle Balls ... and my 11 month old daughter is captivated too.
I have some wishes to make it more "realistic":
1. Make movement of the balls more sensitive to the real location of the iphone - like those labyrinth games. Now it feels like it only recognizes which side is down, but not how upright the iphone is hold.
1b. ... make them go crazy by shaking the iphone.
2. Add a more realistic sound - like small metall/plastic balls hitting the wall instead of "bongos".