One consideration, that could be solved:
On my Nexus S 4G, the headphones jack is on the bottom next to the charging port just like in the iphone speculation pictures. If I am in my car, and it is plugged into the aux port on my car and car charger at the same time, often there the interference from the charging will affect the sound.
This is not an issue of the phone, it's an issue of having the analog audio cable so close to charging wire. Buying an insulated audio cable would fix the problem, or putting the regular audio cable through a magnetic loop would also fix it.
This hasn't been an issue on the iPod touch because I think the 30pin dock connector forces the audio cable to be far enough away.
Just something I am sure Apple will consider.