I don't like the fact that it is stretched vertically but not horizontally. Would have really made more sense to keep the aspect ratio at 3:2 and bump the resolution to something like 1100x730 on a 4" screen. It should give them a PPI of something like 330 which maintains the Retina Display and it means apps will be forward and backward compatible. The size would also be great as the screen would be about 5,62 cm across and about 8,5 cm vertically. Which if you use the current phone as a model for the space required for the home button etc means the end phone will land up with dimensions of approx 123 X 62,2 . Which isn't a dramatic increase from the current phones dimensions of 115,2 X 58,6.
Also I would have had the back plate with thinner sides and then a taper across the back, a mixture of the 3G and 4 design is the easiest way to describe it, done all in aluminum. I find the current set square design tough to pick up off of a flat surface if it is out of the cover and I always fear the rear glass is going to get scratched, also it makes the phone much more slippery which isn't what you want when one drop can mean a shattered screen.