I’m very much surprised that Apple is taking such a big stride here. Until Gurman’s story, I was working on the assumption that Apple would take the obvious path when it removed the physical home button. That would mean drawing a circular button in software in the same place where the button would normally be.
Apart from the removal of the indentation, the navigation would be the same. Click to go to the home screen, long press to activate Siri, double tap for multitasking. Instead, Apple is doing something much more drastic based around edge-swipe gestures.
Whilst the description of how it works sounds reasonably intuitive (although there are gaps in this report about some of the finer details), it is different enough that the usual appeal of a new iOS device (‘you already know how to use it’) won’t apply.
It will be especially weird in Apple Stores, where the company will sell two new iPhones with very different navigation interactions (the 7s phones retain the home button, so it’s just the OLED phone getting the new swipe gesture stuff).
On the other hand, assuming that this is the ultimate direction for all iOS devices eventually, rolling out new and ‘hidden’ gestures to a high-end model first is perhaps the best transition plan Apple could pull off. By its premium nature, the iPhone 8 will be bought by a lot of early adopters and techies first, who are more accustomed and responsive to change. That group can lead by example, almost, before the new UI is used by the more mainstream population. People will see iPhone 8 users in the wild and acclimatise to it, if only subconsciously. It’s not seamless but it certainly helps bridge the gap between the two paradigms.