What must the new iPhone have for you to upgrade?
I've had every iPhone save for the 3G, and obviously only a couple have been through a subsidized upgrade. All of the models save for the 3G have had features that made me decide I had to have them even though I had the previous model. However I think the new iPhone may the 2nd generation I skip. With the larger screen seemingly confirmed and LTE basically a given I still don't think its enough to justify a upgrade from the 4S. Before I go on I'll explain what caused me to upgrade (or not in the case of the 3G) in each of the generations.
3G: faster network didn't matter to me b/c I was mostly on WiFi, hated the plastic design, so no upgrade
3GS: has all the improvements of the 3G plus it was faster, had the gyroscope for gaming, had video recording
4: loved the design, camera was finally more than passable, retina display
4S: Siri, leap in camera technology, much faster CPU/GPU, HSPA+ which is fast here
So in retrospect, for me at least, just increasing network speed hasn't been enough. Usually a better camera, device exclusive technology, faster chips, and a better screen is what has caused me to upgrade. From the rumors we are looking at a redesign, a taller but otherwise same screen, and faster network speeds. That makes it more 3G than iPhone 4 to me. So unless theres a Siri-type of feature I think I'll be passing on the new iPhone.
What features are you hoping for?