That Gamecenter icon is awful, looks lie a 4-in-1 game pack.
It's also really inconsistent. Some have circles with zoom lines behind them, one is a phot of a flower, the weather icon gives an icorrect tempreture, some have slanted green lines and the other one is just aboring flat orange. And what's the deal with not all of them having that glare overlay?
Yeah gotta say I much prefer the icons and drop shadows on iOS 6. Flat barebones icons are not pleasing to the eye or brain. I think that if Apple is really set on this "simplicity" trend, they can still show some artisanship by creating more intricate, finely detailed icons.