So what's the recommendation?
In future, at public air displays:
1. Pilots shall ---
2. Aircraft shall ---
3. Organisers shall ---
If we are going to learn a lesson, we need answers to those questions -- unless we accept this was just 'one of those things, a tragic accident'? Are there any lessons that can be learnt from overseas? Maybe there is a template in another (preferably English-speaking) nation that can be copied and pasted into our own UK regs? In what way are the FAA rules different? Is theirs better than ours?