You just ain’t using it right. Ken Burns–or rather a relevant chunk of a cloned Ken Burn’s Cerebral Cortex–is actually built into every Mac with T-bolt. You need to make sure the keyboard mic is on, that you are standing directly in front of the computer’s camera, and then talk to him, adding clear, broad gestures as you speak. “Ken, a little to the left, hesitate without a full stop, and now, IN!”
You will be amazed at how well it works. Thing is, it takes about 20 min. for the speech/motion recognition to kick in. So, just go to the store, pick an iMac and keep talking to it. Call it “Ken” numerous times. It really likes that. Be very fluid and BIG with your gestures. Imagine the most gregarious symphony conductor, and then, take it up a notch. I think, after twenty minutes of doing this at the Apple Store, you will be shocked by the response you receive.