I don't know why everyone has such a problem with the dock connector. Apple has managed to keep it elegant in all of it's devices, but it's still 10 year old technology. BUT, by keeping it on there, Apple has retained it's commitment to products that iPod owners may already have, I have a 7 year old iPod speaker dock, I use it for my iPhone. I wouldn't be heartbroken if it didn't work that way, but it is a nice touch.
My grandpa always said, "If it ain't broke, don't fix it". All of the arguments here have been how mini-usb can do everything the dock connector can do, but nobody has shown anything that mini-usb can do that the dock connector can NOT do. There are advantages yes, size isn't one of them because the dock connector still fits, beyond that is the plethora of cables that most people have for various mini-usb devices, but lets be honest, many MANY iPhone owners have a stack of those dock connector USB cables from all of their iPods, I myself have 4 extras in a drawer, plus one for my iPhone, and one for my iPad. They can be had online for under $5. There are TONS of folks who have neither USB dock cables NOR mini USB cables, so either way they are buying cables.
I really don't see a need to change the iPhone to use mini-USB, yes it's big but, it's just as fast and capable as mini USB.
-John