Historically Apple have held back certain features of iOS updates to make them exclusive or premiere them on new hardware. They did this with iOS 5 and Siri, we didn't get to see Siri at the last WWDC but we did see the feature with the iPhone 4S announcement. There are certainly some features in iOS 6 that we haven't yet seen, that could either be coming with the iPhone 5 announcement or will be exclusively available on that product. I believe one of those features will be an NFC payments system, to work with the new Passbook app. A new screen size could also mean some resolution independence features, to allow for better scaling at different sized screens. What do you think the new iPhone will bring to iOS 6 that we are yet to see?