“When I first upgraded from my iPhone 4 to the iPhone 5s, I immediately noticed an incredible upgrade in the clarity and sharpness of the larger 4-inch Retina display, but also some usability issues that plagued my iPhone usage experience for the following months,” Jordan Kahn reports for 9to5Mac.

“That’s why I’m excited for the pixel tripling 3x mode at 1704 x 960 resolution Apple is currently testing for the iPhone 6, but simultaneously worried about the day to day use of iOS on a larger 4.7 or 5.5-inch device,” Kahn reports. “Apple currently recommends developers focus specifically on the upper left portion of the iPhone display for important navigation functions and considers the lower right portion of the screen ‘less important.’ That’s not going to fly with a larger 4.7-inch+ display, and it’s got me wondering if app developers will have to fundamentally rethink the layout of apps in addition to any changes to support the next iPhone’s increased resolution.”

“The question is whether or not Apple’s standard navigation buttons and recommendations for app developers will need to change to accommodate a different experience with the larger display,” Kahn reports. “Even if Apple and developers address these usability issues that get introduced with the larger display, perhaps a market for a 4-inch or smaller high-end smartphone will emerge in the process. I’m not just worried about the navigation problems, I’m also not too excited about lugging the larger device around in my pocket.”

Much more, including screenshots and videos, in the full article here.