A 5.7" iPhone in combination with iOS 7 would be a match made in heaven. Let's face it, the 4" screen is no longer effective or enhancing. The strain on the eyes is too much to bear. It is torture. And while on torture, the iPhone badly needs Swiftkey and/or Swype keyboards. And soon. Agree with others that waiting a full year for the rumored iPhone phablet is way too long. We need (nay, demand) it in 2013. The low cost and 5s versions can certainly wait.
The 4" screen was never enhancing. It was just their way of keeping up with the times technically by saying they have a 4" screen. It is not larger, it's just longer. Please save me the technicalities of what larger truly means to anyone that loves to argue the point.