Whether your thumb can reach all important UI elements is mostly a question of UI design, not of screen size. And even on 3.5" you can get it wrong, as shown by the iPhone lock slider with its terrible placement for thumbs. With only a few models to support, iOS developers have it relatively easy, though, they can design not only for specific resolutions and screen sizes but also device shapes.
It's interesting that Siri kind of opens the path to a functional smartphone with much less reliance on the screen. So that could give Apple the opportunity to split their product line into a larger, browser/reader/games focused iPhone and a smaller, PDA focused "iPhone Nano". Or they could just create an iPod Nano-like Siri communicator.
It's interesting that Siri kind of opens the path to a functional smartphone with much less reliance on the screen. So that could give Apple the opportunity to split their product line into a larger, browser/reader/games focused iPhone and a smaller, PDA focused "iPhone Nano". Or they could just create an iPod Nano-like Siri communicator.
I really don't see how the usage pattern is much different from the PC market.3D performance is a bit of an odd case though; some people love playing not-so-casual games on these devices, others just don't care. Because of that I expect you'll eventually see a phenomenon where SoCs either have a *lot* of GPU performance or very little - there won't be much of a "mid-range sweetspot" like there is in the PC market. Or maybe not - we'll see what the market looks like in a few years.
3.7" with the same resolution is the worst they could do IMO.The skeptic in me thinks 3.7" Horizontal Edge-to-Edge with the same 960x640 resolution is more likely for the iPhone 5 though, but we'll see.
Most iPad apps would be completely unusable at that size. Resolution matters much less than physical size for touch UI design.In the quest for pixel density, Apple could leverage the 150K+ apps built for iPad and increase the phone's resolution to that level. That would be a poor choice versus making a clean break for a much higher resolution corresponding to a larger screen size, though.