A friend was a flight attendant on the recent suicide-by-aircraft-engine-injestion incident. People don't listen; they take videos, they grab their rollerboards and everything else, they do stupid things (and apparently some flight attendants freeze up and forget to open their door). Just to throw it out there, the real reason you should not take a bag with you is it will greatly increase the risk of injury as you evacuate. Someone at the bottom of the slide is supposed to help you stop-- if you take them out with your baggage that is much less likely to happen. If it is important, have it on your body at least for taxi, takeoff, and landing.
Safety briefings really need to change. They need to be compact, concise, and focused on the high risk events. They don't need to be comedy, they can't be advertisements, and they need to have a system to make it permanent memory for people that do fly a lot, kind of like education.