Check out this stunning iOS 8 Mission control concept by designer Bill Labus.
“I find double-clicking the home button to be irritating- there’s a noticeable delay between the second click and the multitasking view appearing, and in my haste I often accidentally triple-click the home button, forcing me to wait while the OS bounces into, and back out of, multitasking,” Bill Labus writes on Dribbble. “Control Center’s bottom edge gesture is far faster and easier to perform, however as I said I do use Control Center frequently as well, so I wouldn’t necessarily want to swap the two and use the home button double click to bring up Control Center.”
So Labus suggests Apple should implement the following: