Some time ago I started to explore a crystal interface concept for iOS 7. I initially looked at the iOS notes app. Another app that I explored and applied the crystal interface concept to recently is the game center app. I believe the game center app would benefit by changing to a slide out nav instead of the tab bar. The reason for this is that “Me tab” and “Friend requests tab” have a lower frequency of use, unlike in say the app store app where you move between featured, updates, top charts and search frequently when using the app, so in that case the tab bar makes sense.
I have also looked at placing more focus on achievements for different games. I am not sure that knowing that you are no. 11,740,241 of 11,988,582 is a necessary stat at this list view level and also creates extra noise.