1) New "killer app" features that are not on old phones - we haven't really seen a big increase in iPhone functionality in a few years. Apple Pay was really the last one. Faster, bigger, better cameras, and FaceID are'nt new use cases; paying with my phone is, using my phone to request taxis is (though this came from an App oviously). Come up with a new use case for iPhones that is compelling enough to make more people upgrade.
2) New iPhone SE model - could be the same body as the iPhone 8, or the iPhone SE. Innovate in the smaller size.
3) Simplify the model lineup. Due to the increase in number of models, the average customer is confused about iPhone purchases and often feels they get ripped off by the expensive model or got pushed the worse model. Have a variety of price points, fine, but make sure that all buyers are happy with the value proposition of their phones.
2) New iPhone SE model - could be the same body as the iPhone 8, or the iPhone SE. Innovate in the smaller size.
3) Simplify the model lineup. Due to the increase in number of models, the average customer is confused about iPhone purchases and often feels they get ripped off by the expensive model or got pushed the worse model. Have a variety of price points, fine, but make sure that all buyers are happy with the value proposition of their phones.