This is tricky. I've witnessed my brother go over the barriers in the Alps 20 years ago (head injuries, broken ankle, broken pelvis, broken wrist, fairly concussed. He was in a state and bike parts, pannier bags all over the place). It's only because he fell through a tree still clipped in the bike that saved him. He was air lifted out of the ravine to Grenoble.
That's the very issue really - it's what is or what isn't the other side of the barrier which makes it so dangerous. I believe no amount of cycle tech or race adjustments could make things better and professional riders will still want to push the limit to please fans, sponsors and themselves. It's the road and location the real threat. It's the nature of the beast too, there's no escaping the ups and downs and there aren't short-cuts, and no I'm not saying let's race in a fully controlled environment like a velodrome either.
Perhaps safety netting on the absolute most dangerous fast corner sections where emergency services would be severely delayed to provide urgent assistance and the consequences of a split micro second mis-calculation would be mortal is a potential answer.
