Maj, I agree with you that a safety inspector at every airfield would be better, however...
Have you seen how much opposition a simple CASA or RAAus ramp check can involves?
Seeing as you've been involved in aviation way longer than I have, you have probably been to an airfield where there are more than one flying school - I fly from one like that all the time, and from what I can hear the different CFI's don't really like each other all that much, now imagine if one had power over the others...
Also with sky-diving, it's usually organized through some club and you jump out of that club's plane, so if you don't behave, you don't get on the next flight, it's much harder to enforce when a lot of people have their own aircraft. Short of revoking access to the field there is not that much you could do, unless that safety person would have almost police like powers, where he or she could stop and detain your plane or yourself if you do something wrong.
Plus as far as I understand it CFI's already have similar powers (certificates, BFRs, etc), the problem is if you don't like one CFI you just go / fly to the next one.
I agree that no HF course or SMS will be perfect, especially if people are just treating it as a piece of paper that you need to have. However, short of putting an inspector or spy at every school, or interviewing schools students to check how safe your operation is, those are the methods that are available to us and organizations supervising us, to ensure at least some procedures are followed.
I know a lot of people in here criticize the HF exam, to be honest I really liked mine. Maybe it was because of how it the course for it was structured and executed, maybe because instead of considering it's just something I have to get done it makes me sometimes stop and think if I really should be flying o that particular day, even if I really want to, or maybe just because I find it fascinating, how a series of really small things can have a great impact on your life.
It's the same with SMS - we're going through setting one up at work as well(not flying related in any way) - is it annoying and time consuming - yes, will it stop accidents, probably not (although we haven't had any yet either), but it has made life easier in some regards, it has made the boss go and spend some money on equipment that's better and safer than what we've had (ladders for example) so I don't take it as a waste of time.