I get the demand for screen size but you're also asking for higher resolution as well. If not doubled again, all apps will look like garbage on that bigger screen. Even if doubled, most will then be somewhat blurry.
I have no doubt they can increase resolution given every android competitor has been able to do it. The larger issue for me would be increasing screen size and resolution without decreasing battery life and killing any chance of one-handed use. There-in lies the challenge and reflects Cook's thoughts that he shared in recent interviews.
I would add the option to quit all apps at once....
Doubling the current iphone 5 resolution would bring it to 2272 x 1280. At 5" that would make it 522ppi. Pixel Calculator - PPI calculator, Aspect Ratio Calculator, Display Size Comparison Tool | PixelCalc.com
Which android maker has done the above? The Nexus 5 is 445ppi. The Galaxy S4 is 441ppi. Android is easier to do this with. iOS doesn't scale and therefore is way more challenging for Apple just to increase screen size because "every" android competitor can do it who don't have to worry about the effect on android apps. It will have way more consequences for Apple since it effects all iphone apps.
I completely missed your point on its affects on apps. I was merely referring to android's ability to increase size and corresponding resolution. So yes, very good point and I apologize that I missed it first time around. To avoid further developer fragmentation, this would need to be addressed.
I would add the option to quit all apps at once....
I know nobody is going to agree with this, but it would be awesome for me if the charge port was on the top of the phone rather than the bottom. That way when you are using your phone while its charging (which I always do) you could hold your phone a lot easier without that charge cord resting in the palm of your hand
A nfc addition would be a killer though! its still good....almost everyone wants the screen size bigger now.so probably anything between 4.5 to 5 would be good probably they are working on iphone 6 for this and 6 will be definitely having bigger screen atleast bigger from 5s eventually they have to do in order to stay and keep the grip in market and to compete with other companies