I have mixed feelings about this. I used to think it needed to be removed. Now, I am not sure. I have given it a lot of thought and I do feel that if we teach good gas management, proper dive planning and a buddy positioning, it should not be needed.
When I say good buddy positioning, I believe new divers should have to swim 15 meters after an exhale to retrieve gas from a buddy. This shows them that staying closer to your buddy is key in reducing risk.
Having said that, I can see circumstances where a CESA might be needed. Diver A gets caught in a current and pulled away from Diver B. Diver A then has a catastrophic failure. But I also wonder what the likely of this event happening is as it seems to be a perfect storm.
I suppose my answer is that I need to think it through more before I settle on a position.