I love how everybody seems to blame their issues on an update. You wanna know what the latest update did? It fixed party issues and fixed an issue with Kinect and the English language. Where in that do you see anything that could affect your power not turning off? The update before that required all free trials to add a credit card, does that have to do with the power not turning off? No. Blame it on the update all you want, doesn't mean you're right. The update doesn't bring problems with it, it simply brings to light problems that were already there beforehand, and makes you aware of them, so you can fix them.
You're not being watched through Kinect, and if you believe you are, simply turn off Voice Data Collection in your Privacy settings.
As for your power issue, it could be an issue with the power supply, in which case simply unplug it when you turn it off. Problem solved.