We have been wondering about this a lot too, but “FightThePowersThatBe” just shared the idea out loud on Reddit. Starting from iOS 4, Apple introduced multi-tasking for iOS, and from then on it allowed you to double tap the home button to switch between Apps. As iOS is now able to multi-task, users can also tap and hold the Apps in the bar that comes up to close already running Apps to save battery life.
If you’ve got a lot of Apps running, and if you close them from time to time, then this feature request should be very helpful for you. Apple should introduce one button that could close all running Apps helping users to be more productive. Don’t you think this is a must-have?
Hopefully, Apple will listen to this.