Reading the documentation for the iPhone software development kit I found this in the iPhone SDK Agreement:
3.3.5 Applications must comply with the Human Interface Guidelines and other Documentation provided by Apple.
In other words: No new interaction concepts, no cool user interfaces, only the same that already is. Apple will decide based on flawed guidelines whether you spent weeks researching and testing your interface or not. Surprising move from a company so focused on being the leader of user interface design.