I dont think Josh's death should be a message or reason to not trust AP. He clearly wasn't using it correctly. Is it disappointing that it didn't detect a semi truck across the lane? Sure. Am I happy the new enhancements will allow it to detect this situation in the future? Of course. But had he been paying attention he had more than adequate time to stop the car. The fact that he never applied the brake I believe is an indication he was significantly distracted.
I love the feature. I believe it removes a fair amount of stress. But it doesn't, and never has, removed the driver's responsibility to stay attentive and operate the vehicle.
I normally don't hold the wheel. I keep one hand towards the bottom. If I see road ahead that I think AP might struggle with, I put my hands on the wheel. If I see road ahead that I know AP will have problems with, or is dangerous (construction zone, for example) I turn it off. I've operated this way for thousands of miles, cross-country, etc.
You just have to pay attention. It's really that simple.