If there is a larger iPhone, I hope it has the same aspect ratio as a previous model so making games for their display is a breeze. (3-4X graphics could have a play but you wont need to resize for 3 different sizes, just 2).
I also expect to be able to develop for the iWatch if the rumor is true, only so I can grab a bag of Funyuns as I watch my dad squint at the small display and curse technology.