Gamecenter
This may sound stupid but for me it seems that gamecenter is not finish build ?
As i understand gamecenter is made like a roundabout were Apple phones and mac's can connect and play games together, but over half the games my mate got is only for Iphone, ipad and can not be found in app store, same problem the other way, i hope this is gonna be better so the gap between available games for phones and app store get smaller.
Also it would be nice with options like, chat on off, send messages to friends etc.