Cult of Mac:
Then we realized that WWDC 2012 wasn’t the first app to adopt Apple’s new look — iPhoto has it, too. Furthermore, almost all of the iPad’s built-in apps — like YouTube, Maps, Mail and more — have sported silver user interfaces since the day they were born.
It seems likely, then, that iOS 6 will move towards making iPhone apps look more like their iPad counterparts. We are expecting to see almost all of Apple’s built-in apps adopting a new look for this summer’s update.
This feels right to me. It's been almost five years since original iPhone shipped with what was then known as iPhone OS 1.0. That's a pretty long time in design, and Apple has never been shy about tweaking it's UI to follow new trends. As a developer, I can't imagine shipping an app on the App Store using the default blue UIKit elements in 2012. At minimum, I'd tweak the colors, and probably add some texture to make things feel a little more current. Let's just hope the changes in iOS 6 don't include brushed metal or (shudder) stitched leather.