iPhone is almost nothing without internet thus it’s just rightful that turning on/off the cellular data and sharing it via Personal Hotspot should be available in Control Center. It's available in Android but adding the two options in Control Center will not hurt Apple's pride but will give comfort to Apple iPhone/iPad users. 

Closing all apps running is also not granted.

With iOS 9 beta, I believe I can suggest these features and hope Apple will listen to my wishes.