That kind of navigation is just as logical on the iPhone. While a fixed button on the front has always implied a singular, central action, removing it--whether by moving it to the side or the more likely option of making it virtual--would take the pressure off of it as a primary tool and open iOS to new kinds of navigation.
A better focus
On the iPhone, the home button is a direct path to our apps. No matter where we are, pressing it brings us back to the icon grid. But on Apple Watch, apps aren't central to the experience. The main screen is the face, followed by Glances. Apps on Apple Watch essentially exist in the background, in direct opposition to the iPhone method, where they're always front and center.
With or without a home button, the iOS home screen is overdue for a change. On Android, an app drawer keeps installed apps out of sight, leaving the home screen free for widgets and shortcuts, and I could see Apple doing something similar with iOS. The new proactive search page in iOS 9 is the first step, and it could become a pivotal screen. By learning which apps you use most and when, you won't need to swipe between pages of icons. Apps you don't regularly use will stay out of your way, and the home button would be less important to navigation.
Apple could solve the problem of constantly jumping in and out of apps by borrowing another Apple Watch feature: Glances. With Glances on my watch, I can get a day's worth of information without needing to launch any of the apps--that's not quite so easy on my iPhone. Notification Center widgets can be helpful in some cases, but the infinite scrolling method isn't nearly as useful as full-screen Glances on my Apple Watch, and I usually find it quicker to check scores or weather by visiting the app on my iPhone, not its widget.
By reimagining the Control Center, iOS could bring a similar swipe-up method for quick actions. People have been calling for a way to customize Apple's quick-launch screen since its debut in iOS 7, but I'd love to see a swappable series of Watch-style Glances that bring quick actions and bite-sized data chunks, so I can rely less on the apps. If I could swipe up to quickly jot down a thought in Drafts or compose a tweet in Tweetbot, I could reserve the full-featured apps for longer sessions, and I wouldn't have to switch between apps as often.
Force of change
Even if Apple does plan to ditch the home button, it's not going to happen this year. But a good start toward our home-button-less future would be to incorporate another key Apple Watch technology. Force Touch on the iPhone 6s is the biggest inevitability since Siri on the iPad.
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