John Gruber on the complaints the iPhone 4s didn't come with a new form factor:
Apple pursues timeless style, not fleeting trendiness. This iPhone design might be like that of the Porsche 911 — a distinctive, iconic, timeless, instantly-recognizable representation of the product’s brand itself.
Spot on. The day before the event I mentioned to a couple of friends that I hoped Apple didn't change the design of the iPhone. I had it in my hand and thought it looked great. It truly is a beautiful design and there's no reason to change it.