Dustin Curtis analyzing the design decisions behind changing the iPhone 5’s screen size:
It’s easy to see Apple’s thinking here – the benefits of having half an inch more of display area far outweigh the downsides in reachability. Every area of the screen is reachable, after all (unlike many Android phones with 4-inch+ screens), it’s just slightly uncomfortable.
You really need to read this entire post, or at the very least the bulleted list of reasons why the iPhone 5’s other design elements makes the 4-inch screen more reachable than it otherwise would be. Things like a thinner phone allowing your hand to wrap around more easily is something obvious, but also something I hadn’t even realized was going on.
Personally I don’t like the extra difficulty at doing rare tasks, and I don’t like the extra height of the phone when in my pocket. However, I love all the extra screen real estate when viewing lists, reading things, and typing — which accounts for about 90% of what I do on the phone. So on the one hand it is a slight inconvenience, but on the other it improves the more routine things I do on the phone so much, that I find it hard to complain about the former.
Overall, the screen size increase is a huge win for users of any hand size.