Speed is the key
It needs to arrive now! it's already hideously out of date when it comes to bandwidth (I just bought a £40 Lobster from Virgin mobile that is as fast).
It can only win over users if the phone is very easy to use, robust, reliable, has good reception and battery life. Nobody wants a poor phone and a poor ipod in one. The phone and media facilities need to be class leading to make up for the ancient data speeds.
At this stage I'm not a fan despite being a recent Apple convertee. Apple has world leading design in many ways, but also poor design in other ways. I love my Mac Pro and Macbook, but I hate their mice (Mighty mouse wireless is too heavy and cumbersome).
They oversimplify things at times and sometimes looks dictate function which is bad news for ergonomics.
Operating such a slick shiny phone with fingers seems crazy, fingerprints everywhere.