Not launching iPhone in several sizes out of the gate or within first three years. This gave a huge opportunity to competitors to get customers entrenched into their ecosystems instead of Apple's. Now it all comes down to Apple getting "switchers" to grow their customer base. Their base would have already been a whole lot bigger if they had offered larger size iPhones earlier on instead of now trying to convince them to leave their large size competitor phone and ecosystem and to now come to Apple with essentially a very similar device offering.
Before voting consider that pent up demand for larger phones has pretty much been satisfied so Apple needs to count on switchers, 2 year or less upgrades, and international growth. I'd guess the all three will be lacking with this edition.