For 2015, iOS 9, which is codenamed Stowe (after the ski resort in Vermont), is going to include a collection of under-the-hood improvements. Sources tell us that iOS 9 engineers are putting a “huge” focus on fixing bugs, maintaining stability, and boosting performance for the new operating system, rather than solely focusing on delivering major new feature additions. Apple will also continue to make efforts to keep the size of the OS and updates manageable, especially for the many millions of iOS device owners with 16GB devices.
If this turns out to be true, it will make a lot of people happy. Stability is one of the biggest complaints in the last year and I have personally heard it from a lot of friends that are Apple fans and developers.