Marcus I would not disagree with you entirely, the one thing I like is the ease of getting rid of the pannier supports. I did look at Jesses which I must admit did appeal to me and their mounting solution, but just did not like the shape of them. Have seen Touratech panniers (normal ones) they are very similar leaving a similar gap on the exhaust side.
I like the idea of being able to take off the frames as well as the panniers, which if I have read Verns site correctly Verns are a little more difficult. Being honest the bike has a mixed life and I really don't want frames/panniers attached premanently to the bike.
Leading on from my last point, my pockets ain't that deep, seeing the cost of 3mm aluminium sheet I could not in all honesty justify the cost of the most popular makes i.e Touratech, Jesse or even Verns. As the chances of me going on LWR trip in the near future is unlikely.
As to an accident having been though one bad one, the speed required to do the things you say would happen I probably ain't going to being smiling anyway and I would have thought me and the bike would have already parted company. Also if you have a look at Boz's trip the panniers are taking a fair battering and are still going.
And lets put a myth to bed, double welding will make the weld very tough but because of the process involved either side of the weld is not as strong as the original material. Rolled joints do not suffer this problem and the top and joint are the best part of 5-7mm thick which makes them far stronger than a welded joint.