“Isn’t it more accurate to think of this as an iPhone 6S in a 4-inch body than as an iPhone 5S with ‘upgraded internals’? Other than the display, aren’t the ‘internals’ the defining characteristics of any iPhone?”
I agree with John. Other than the screen size, this phone will feel a lot like an iPhone 6S. And because I love the smaller size, I personally think it will have the best of both the 5S and 6S.
Prediction: this phone is going to be much more popular than people expect. I won’t be surprised if it takes the 6S Plus’s spot as the 2nd most popular iPhone.