If the iPhone 5 debuts with a four inch touchscreen display, does that mean it still needs to have a new design, like a teardrop shape? iPhone 4S has been a success in its first few weeks of existence, but because it looks so much like the iPhone 4 on the outside, many Apple fans are still clamoring for a thorough redesign, starting with a larger screen. Many Android devices are already coming out with screens that exceed four inches, so a four inch iPhone would make sense in that regard.
But if the screen size changes, why not go for an all out redesign with a tear drop shape, different colors and more hardware additions/changes. Apple no doubt has many of these ideas already sketched out, and Steve Jobs is said to have been involved in creating several devices that will still be coming out for the next couple years. So while a completely new design would not be out of the question, those designs have their limitations and Apple likes to prioritize things like battery life and ease of use.
For a larger screen and things like 4G capability, that battery life becomes a prime concern, and was cited as such when the iPhone 4S came out. Until new battery technology emerges, these types of concerns will be a big part of the smartphone world. Because of how power intensive so many devices are now, battery fatigue is one the most popular complaints about mobile devices.
But other design features both inside and out would not necessarily need to subvert battery life. Things like a near field communication chip or fewer physical buttons would be one way to the iPhone design without affecting battery life. Furthermore, changes could be made to the iOS system itself to make battery life more acceptable. iPhone already has a decent battery, so Apple is likely to maintain that. A four inch screen is not a substantially larger one than currently exists on the iPhone, but other changes are simply to far in the future to know about.
Let us know in the comments if you think the iPhone should have an even bigger screen than four inches.