We could probably create a ‘law’ – along the lines of Godwin’s law or Murphy’s law – that states that with every iPhone release, there will be multiple rumors about it being designed with a larger screen. Of course, the upcoming, next-generation iPhone is no exception. Reuters has covered a rumor stemming from South Korean publication the Maeil Business Newspaper, which states that the next iPhone will have a 4.6" Retina Display screen.
While Apple’s rival phone manufacturers have all adopted larger screen sizes, Apple have remained firm in maintaining the 3.5 inch screen size throughout every single iPhone release since the inception of the device in 2007. In response to some debate and rumor that had taken place surrounding the release of the iPhone 5, blogger Dustin Curtis wrote a pretty magnificent post explaining the likely design decisions behind the iPhone’s retained and notorious screen size.
Basically, the reason behind it is so that it’s easy for most people to move their thumbs to each part of the screen with ease. This is something that becomes increasingly harder or uncomfortable to do on devices with a larger screen, such as the Galaxy S II. As you can see in the above image, Curtis produced a rendering that depicts a sort of comfortable "thumb radius", showing parts of the Galaxy S II that are out of reach.
I pulled out my iPhone 4 to do a quick test, and it turns out that when you hold the iPhone in your left hand and articulate your thumb, you can reach almost exactly to the other side of the screen. […] It is almost impossible to do this on the Galaxy S II.
In my opinion, a larger screen is more of an advertising gimmick. People often think that bigger is better – especially people who may wish to watch movies on their phone – but to me, it is more of a usability impairment than a positive design choice. Nevertheless, as there are constantly rumors of new iPad screen sizes, the dead horse section of the Apple rumor mill will continue unleashing these rumors of Apple increasing the screen size of its next-generation iPhone, even after the next iteration of the device has a 3.5" screen.
So the verdict? This rumor is highly unlikely. Should Apple create an iPhone with such an enormous screen, pigs will fly and hell will freeze over. And, in an even more unlikely twist, they’d create a smaller iPad.