If you compare the iPhone 5 with the iPhone 5s in terms of its responsiveness which is a measure of the speed of its processor, then for most everyday tasks such as booting up, shutting down and browsing websites, the iPhone 5s is not noticeably faster than the iPhone 5. However if you use it to play the latest 3D games, the difference is obvious. This data point leads one to believe that Apple is trying to push the envelope of what a smartphone is used for rather than target good enough performance with longer battery life as Intel has done with its Haswell processor for PCs. Indeed in its introduction to the iPhone5s, it highlighted that the A7 was "desktop class".
In a survey of iPhone users, a large percentage wanted Apple to improve the battery life of its next phone. This, when its already providing all day battery life for web browsing. Clearly this is not the path Apple has chosen to take.