I don't follow the UI inconsistency argument. The novelty of iOS is that every function is contained within an app. Passbook being different from Music doesn't reflect UI inconsistency any more than Twitter being different from Facebook. iOS is a blank slate, and always has been. The apps should be designed to be intuitive and easy to use based on the functions that they perform.
You might as well tell me the UI is a disaster because Calculator and Calendar don't have the same UI. It's an argument that ignores how iOS is designed because for reasons passing understanding some people really, really hate skeuomorphism and need to lash out against its implementation. But UI consistency as an argument against skeuomorphism is an empty one.
UI simplicity and intuitiveness would be better arguments against, but those only apply to the extent that skeuomorphism detracts from simplicity and intuitiveness, and there are fleeting few examples of that in iOS.
The best comment in the thread and of course, everyone ignores it. This guy has it right.