The most surprising thing about the iPhone 4S is that people were surprised by the iPhone 4S, for there is ample precedent to the company both confining upgrades largely to a speed bump and to saying no to a host of potential new features. As to the former, the iPhone 4S is straight out of the playbook of Apple's successful upgrade of the Apple 3G to the 3GS, although the competition wasn't as strong as it is today.
Similarly, when Apple first lowered the price of the iPod touch below $200 in 2009 amidst widespread speculation that it would add a front-facing camera for FaceTime (which it did in the next generation), the company noted that it didn't think the product needed any more "stuff." So, what, then, defines the iPhone 4S? The differentiators can be thought of as four "Ses."