The iPhone 6 is fine, sure, but with its massive footprint it's also kind of a hassle if you have tiny hands. Take navigating back to the inbox from an email in Mail, for example; the gymnastics your thumb needs to undertake if you only have one hand available are Olympic-level.
Enter Halo Back: not a Gwen Stefani remix but a smart screen protector that uses a capacitive channel to link the dead bit of glass by the home button to the top left corner where the back button lives, thus essentially putting a back button within easy reach of your thumb.
Not to question the all-mighty all-powerful all-knowingness of Apple but this seems like what we in the biz call Quite A Good Idea. You can back it on Kickstarter here.