I sketched the GAME CENTER podium idea out the way I'd want it to be.
I don't like your icon, but not for the reason you might think. Take a look at this:
What I've done is (roughly) overlaid parts of the iOS 7 icon Grid System over your icon. My problem is that no part of your icon aligns with this grid, whereas all of the other icons in iOS 7 do.
I'd love to see if you could reshape and re-postition the podium to fit the Grid System. Make sure none of the podium goes outside of that outer circle (the reflection is fine), and also you could align the bottom of the podium to the bottom green line I drew on. Use this as a guideline. This could also help to see how other icons make use of it.