I agree! I don't have 4.3 beta but I was just "mock" swiping and four and five fingers does seem awkward on the iPhone but 3 felt pretty natural actually.
4 or 3 does not make that big of a difference in may eyes. If your able to cover the dock with 4 fingers your able to swipe with 4 fingers. I would like to have the possibility to do it if I want. Make it optional I would say.