The closed architecture and opposition to having people "hack" their iPhones to add features and functionality says, in effect, "we know what you should have better than you do". There is another example of something on the iPhone which says "we know better than you do" even more strongly, the spell suggest/correct. You actually have to opt-out to reject the iPhones suggestion as opposed to opting in to accept it. Really annoying given how frequently people use abbreviations and shorts when text messaging. Not only is it presumptive, its overly aggressive.
The other big problem I have with the iPhone is the lack of cut 'n paste. Cut 'n paste is one of the most powerful and important cultural forces in the last 100 years. See my essay: The Frankenstein Aesthetic: Cut n' Paste.
Digitally empowered "Cut 'n paste" has made possible the emergence of what Larry Leesig call's "Read/Write Culture". If you haven't seen his TED talk, do so, right now. The current omission of this feature reinforces my belief that these days Apple Computer is less of a company devoted to "thinking different" and empowering the creative class than it is about the efficient delivery and sales of old world media products like movies and music that are intended to be passively consumed by well behaved consumer.
(This is such a sore point for me right now becuase I am away an blogging remotely with my iPhone. Adding links and embedding oics and videos is nearly impossible.)