There are two aspects to airshow safety management.
(1) Minimising the risk of a crash.
(2) Ensuring that if that crash ever does happen, it does not affect anybody on the ground.
This is built around the understanding that airshow pilots are knowing participants who understand and accept the risks involved in what they're going.
Historically, and rightly in most people's opinions, (1) is minimised but can't be eliminated completely. (2) Should be eliminated completely, as no "innocent bystander" should be subject to risk of loss of life due to an activity they have no understanding of or control over.
Where Shoreham went horribly wrong, is that (2) failed. NOT that there was a crash - albeit that there are clearly lessons to be learned from it, but there have been crashes before and the odds are that there will be crashes again. But virtually all of those other crashes did not kill uninformed bystanders.
In many ways it reads to me that the failing at Shoreham was not because the rules were lax, but that the existing rules weren't applied as fully as they should have been. However, it also caused a review of everything, and in the CAA's perception, gaps were identified and closed; others may disagree with the detail of the perception, but I don't think that anybody's disagreeing that Shoreham should have been prevented by some aspect of better airshow management.
A high energy show at low level in a vintage warbird is a very thrilling thing to watch, in part because of the risky nature of the activity. That should be an acceptable activity, but only where the pilot's is the only life at risk when doing it.
G