Here we go again.......
1) Dr Richard's research paper wasn't about barefoot running. He was simply stating that there has been no data supporting the hypothesis that modern cushioned/supportive shoes help to prevent injury. This is surprising as, considering the budget and research facilities of Nike etc, if their shoes do perform this miracle then you'd have thought they'd have put the work in to show it. Also, as I said, he put out an open invitation to the running shoe manufacturers to back up their claim and no-one, as yet, has. Finally, you don't tend to get something published in BJSM unless it is valid (in strict scientific sense) and has been subjected to extensive peer review... it's not a mickey mouse journal.
2) Sorry, didn't feel I could write a summary of the whole paper but all other variables such as volume, speed, terrain etc were put into the analysis and cost of running shoes came out with the strongest correlation to injury. Again, I think the American Journal of Sports Medicine where his paper was published would have checked for such simplistic flaws in his analysis.
3) CL, I'm sorry but impact force studies have been done and the data all points to the fact that a barefoot/lightly shod runner will strike with less force than one in heavily cushioned shoes. Your ball/rock analogy is one of your typical "irrelevance granades" as energy returned is not the issue but actual impact force. As is your jumping from a tower analogy, spectacular, showy but total BS. I back-up my arguments with sound scientific studies you seem to prefer dreamt up analogies , gossip on the web or the Daily Mail. At McGill University in Montreal, Dr Steven Robbins and Dr Edward Waked performed a series of tests on the landings of gymnasts. They found that the thicker the mat, the harder the gymnasts stuck their landings. Instinctively the gymnasts were searching for stability. When they sensed a soft surface underfoot, they slapped down hard to ensure balance.
4) This example simply illustrates that the heel has not evolved as a landing/striking surface (whether jumping or running) and only by artificially cushioning it have we allowed it to become one. None of us should be heel-strikers, it's not natural for anyone but conditioned by a lifetime wearing inflexible soles.