I posted the below excerpt in August 2013, before iPhone 5S was launched on my biggest reservation about a bigger (than 4") iPhone. Now after a few months and after the launch of the iPhone 5S, speculations are at their peak on not one but two bigger screen iPhones from Apple in 2104 and that too from the WSJ. With the number of rumors on this topic, I think it is almost certain that Apple will release, at least one bigger screen iPhone in 2014. But I have not got a satisfactory answer to my previous question so far.
I have used a couple of my friends' Galaxy S3 and even a Galaxy Note. I cannot use them as a phone and I am sure many smartphone users are like me. You cannot simply use a humungous phablet as a phone DOT. The reason is that its impossible to use them with one hand. I can use it with two hands like I use my iPad Mini , but that's why I have a tablet. However I do understand that a lot of users, including me, would prefer to use a single device that is both portable as an iPhone and powerful and convenient as an iPad. But can you have the cake and eat it too?
So how is Apple going to solve this problem of one hand usability of the rumored bigger screen iPhone 6? A couple of things I could think of here are iOS optimization for a larger screen iPhone and getting rid of 'wasted' space around the iPhone that is not the touch screen. The first part of it was briefly addressed by iOS 7. The biggest qualm for me about the bigger iPhone is how am I going to access the top left part (as a right handed person) of the screen with one hand. For example, two iOS 7 Apps (above), Photos and Music Apps, both need you to touch the top left part of the iPhone screen to navigate back. They will be impossible to reach with a bigger than 4" iPhone with the current design. Apple has made some gesture modifications in iOS 7, like for example in Safari, a swipe from from the bezel can take you back (or forward), though the button to navigate back is actually in the bottom left of the screen instead of top left like the fore mentioned Apps as well.
The second thing Apple could do to increase the screen size of the iPhone while trying to maintain the one hand usability of the iPhone, is to get rid of the wasted space around the iPhone's screen, i.e. the bezels. Look at the iPhone 5S, there is almost 40% of the phone's real estate that is bezel. So if Apple can make these thinner or even go away completely, the iPhone can potentially gain more screen size. An interesting info graphic (below) was posted on 9to5mac today on the ratio of screen size to smartphone dimensions for many smartphones.
Note that however, these 'wasted' bezels have a purpose in the iPhone's design. They house things like the Touch ID enabled Home button (it is fair to assume that Touch ID will be a default feature in future iPhones), the front facing camera and the speaker for making phone calls (yeah lot of people still make phone calls on the iPhone). Also on the back of the top bezel of the iPhone is the entire back (primary) camera housing. The only bezel real estate that is not used 'effectively' is the bezel on the sides of the iPhone. But there is not much real estate to gained from them and making them really thin or non-existent might affect holding the iPhone itself (palm touches!) and designing cases for the iPhone.
A couple of rumors appeared today on the next iPhone. The first one is that Apple will not use Sapphire screens for the next iPhone and that is on the contrary to many reports that have suggested otherwise. However let's concentrate on the the second rumor as it is more relevant to this post, that Apple is working on bezel-less displays and that it is prototyping one that includes a fingerprint sensor.
Though 9to5Mac calls this a bluff (above quote), I think that there might be something worth looking into here. Thinner bezels and finger print sensor, means the bottom bezel has to stay (at least for now as this entire touch screen serving as a finger print sensor technology sounds too far fetched). Hence the only 'bezel cutting' that can be done is on the remaining three sides. Of course Apple could do both, i.e., further optimizations in iOS 7 (or iOS 8) to include more gestures to ease one handed use and/or thin down the bezels to enable a more accessible, but bigger screen iPhone. 2104 does sound like its going to be a fun year in the Apple sphere!
UPDATE: Looks like Sapphire display rumors are back [via 9to5Mac] and this time have come with a pixel density number of 441 ppi and the already known two models of sizes, 4.7" and 5.5". And as expected (after lower than expected sales, according to Tim Cook himself), iPhone 5C will be scrapped, but iPhone 5S will remain, so three iPhone models huh!