Forget about the iPhone 6 Plus, Apple Pay and even the company’s bold step into wearables. The most important thing Apple announced last week just might be the Apple Watch’s pressure-sensitive screen.

The cool feature, which Apple calls a flexible retina display, will appear only on the Apple Watch to start, but if the innovative display is successful, it will represent a major step forward for touch computing.

At its core, the “press and hold” mechanic is the return of the “right-click” that turns word processors, spreadsheets, and StarCraft into powerful tools and experiences. In the short term, it enables Apple’s UI team to squeeze much more functionality out of the watch’s limited real estate. But if the trick is applied to larger screens, unsightly user interface chrome could be minimized or eliminated entirely by subordinating it into context-specific press menus.

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Currently, fully featured enterprise apps like Gmail, Excel, and Photoshop are awkward to use on iOS. “Hamburger buttons” are proliferating in apps as users demand more from small screens and designers attempt to translate clunky desktop design patterns to mobile devices.

Although the Apple Watch is flailing to find a killer app, this subtle UI tweak could help move critical functionality from PCs to smartphones and tablets. For instance, double-tapping a word in a text editor highlights it for selection, but pressing it could cycle through font styles rather than forcing the user to dig through an obscure menu. If a user taps on a photo in the eponymous app, a “copy” option pops up, but with this new technology, pressing and holding could open an editing tool palette. Likewise, Reachability, a new iPhone feature that moves the user interface closer to the user’s thumb when the home button is double-tapped, is a nod toward keyboard shortcuts. Viewed in the context of Continuity, the iOS 8 feature that lets you seamlessly transfer actions between an iPhone and a MacBook, Apple’s embrace of UI input complexity could be positioning iOS to supersede OS X as the primary operating system for most users.

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While introducing the iPad, Steve Jobs predicted that general-purpose PCs would become the trucks of personal computing, and his vision was prophetic. In 2013, smartphone and tablet sales outpaced PCs by a six to one margin. Based on strong demand from Asia, more “phablets,” or smartphones with screens larger than 5 inches, will be sold than laptops. Earlier this year, mobile Internet use surpassed PC Internet traffic. Consumers are clamoring for larger smartphones and smaller laptops

How much longer must Moore’s law work its magic before the iPad and MacBook Air are functionally equivalent for 90 percent of use cases? Microsoft’s Surface line shows a hybrid approach is possible. Proper keyboard and mouse support would go a long way to close the gap, but building pressure sensitivity into the touch interface supports similar levels of complexity without entirely abandoning the platform’s unique virtues.

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iOS was hailed as a radical reinvention of computing. Decades of UI cruft and arcane conventions (Ctrl+Alt+Delete, anyone?) were cleaved, like the Gordian Knot, by imposing radical limits on what the devices could do. Seemingly must-have features like cut and paste were controversially absent, but the results were inarguable as YouTube videos of precocious toddlers and cats using iPhones proved Apple right.

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