MobileCrunch has an interesting post up about five things the iPad has and does that Apple would do well to bring back to those of us using the iPhone. I think we'll see more of these as we go along (especially as, you know, some of us actually get to touch and use the device), but this list is a good start.
Bluetooth keyboard support is something that only jailbreakers could do on the iPhone, but it shows up day one on the iPad. The iPad, according to those checking out the SDK code, will also be able to share files with the desktop, and different apps on the iPad will even be able to identify themselves as owners for certain filetypes, which is another cool trick that Apple should teach the old iPhone dog. And of course, that processor -- we can probably expect to see a smaller version of it in a future variation of the iPhone sooner or later, since Apple is always fighting to get battery life and speed to the max.
Of course, the iPad and the iPhone are two different devices, and Apple will want to keep some things separate -- as we've heard already, there are certain interface guidelines for the iPad that the iPhone will never use. But especially if we see the expected update to the iPhone later this year, it's a good guess that we'll also see some of the iPad's more reusable features find their way to the "iPad mini."