That all makes sense, of course. Aesthetically, I think most of us love the idea of a completely flat slab in theory. But I think Apple correctly factored in the camera and battery-life expectations of most potential Air customers.
When the phone’s design was first rumored, I couldn’t understand why the wide bump was needed, but it all makes sense now. Moving the phone’s critical circuitry to the bump is an incredible technical achievement, and was necessary for them to obtain a battery big enough to hit battery-life goals.
For me, the camera is where I’m really surprised (assuming it works as well as advertised), and this is what pushes me into the “buy” column. But I realize not everyone needs that.