The iPhone was meant to be able to be held with only one hand, and I would love to see the person who can hold their phone, and swipe left or right with 4 or 5 fingers at the same time.
Well, it would have been nice to at least have an optional up swipe to reveal the activity tray, similar to the down swipe we have to reveal the notification center.
I really dislike double-clicking the home button for that as I find it disruptive.