This seems logical: bigger cameras should mean bigger lens and bigger sensor. That means more light, which should translate into better images. It’s somewhat true, but there are also constraints such as depth of the device and the amount of space is required between the lens and the sensor. At the moment, all we know is that the chassis “hole” is bigger.
That said, it is reasonable to think that the iPhone could use a slightly larger sensor and lens. As it stands now, Apple’s line of phones provides a very decent experience but isn’t really at the top of the game right now. The Galaxy S7, the LG G5 and the Huawei P9 have all introduced excellent cameras innovations recently, with the S7 being the overall king of the hill for its overall camera experience and performance.
The camera is probably the #2 priority when it comes to smartphones, and Apple had historically had an excellent leading role until the last couple of years when it started to be upstaged by competitors.
With iPhone sales slowing down for the first time since its inception (-13%) as predicted, Apple is probably very motivated to keep competitors at bay, or at least find the right balance between high-performance components and high-profit margins.
The iPhone 7 new camera is something we are looking forward to, and we’re certainly hoping that the rumors are the reflection of significant improvements in photo performance, and not simply a design gimmick to “project power” rather than bring it to bear.
Note also that iPhone 7 Plus rumors mentioned the possibility of having a dual camera and camera sensor. Both LG and Huawei have explored this possibility in different ways. LG opted to provide a wide camera lens, which makes the LG G5 uniquely positioned for wide-angle photos, while Huawei has a dedicated luminance lens/sensor to improve imaging performance.
Because of the physical size limitations, the future of mobile camera will probably rest in the utilization of more than one lens and computational photography, something pioneered in larger devices such as the Light camera.