Apple...4.5"+ or bust! The market is demanding it!
4.5 is horrible. I can almost say with 100% certainty that Apple will NEVER market a 4.5" iPhone. And whatever they wind up doing, there will only ever be 1 size iPhone. Smaller tablet? Maybe, but not multiple sized phones.
Maybe Apple could make a nice 4.5" device, but at that size it splits the market because there a ton of people who hate (including myself) grossly big phones.
~4" is the goldilock's zone.