A "big screen" event if they released both a larger iPad and iPhone at the same time. I do not know if I would up grade or not. I am pretty happy with the 5s, it depends on just how much larger the phone is. If Apple pulls some magic and gets a 5" screen in without making the phone much larger then I would be very interested (i.e. screen to the edge).
I was doing some research on cameras.
The cam on the Note 3 is better (or at worst: equal) in all categories but one.
That would be in flash lighting color rendition.
Two LEDs on the 5S apparently are no gimmick.
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Apple has so far made screen resolutions to ease game scaling for modest processors.
With the new 64-bit monster cpu and graphic processor, maybe they'll cut the cord and finally put in a 5" 1920x1080 (or higher).
I'm happy with my iPhone 5. I think I'll keep it until the battery dies, and maybe even past then, with a new battery. A slightly larger screen would be nice, but not that nice.