Not sure if anyone has seen this yet but heres a weblink to an app that enables the back button to kill apps on stock TW. Obviously i take no credit for this just thought id share it. And yes, this works for our device!!
http://gs5.wonderhowto.com/how-to/use-your-back-button-force-close-any-android-app-spot-0160683/
http://gs5.wonderhowto.com/how-to/use-your-back-button-force-close-any-android-app-spot-0160683/
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