Well I did mean app developers should probably start making it so that the 6+ uses iPad apps. It seems like it'd be possible if the Apple's apps make a differentiation between the 6 and 6+.
iOS8 has a new metaphor for making the UI more responsive to different real estate. Their called size classes iPhone 6 is classified with the same size classes as iPhone 5s. So, I don't think you'll see "innovative" uses of the new real estate in the iPhone 6, but you're going to see some really funky stuff on the 6+. As you've seen in Apple's apps, that's because the landscape "size" of the width is considered regular, which opens up tablet-like uses of that width. (e.g split screen views).
(Compact meaning small and Regular meaning "big" from a layout perspective)
iPhone 5 - 1136 × 640 (regular / compact portrait , compact / compact landscape)
iPhone 6 - 1334 × 750 (regular / compact portrait , compact / compact landscape)
iPhone 6+ - 1920 × 1080 (regular / compact portrait , compact / regular landscape)
iPad 2, iPad Mini - 1024 x 768 (regular / regular portrait , regular / regular landscape)
iPad Retina - 2048 x 1536 (regular / regular portrait , regular / regular landscape)
While, you can tell that an iPhone 6 is very comparable to the resolution of the non-retina iPad, realistically, the available space isn't sufficient to allow use of the "regular" metaphor throughout because touch points are much smaller on the iPhone than the iPad. From usability perspective, you'd be begging for imprecise touches because lists / UI elements / whathaveyou would too crowded for the imprecise nature of finger touches.
