I think that 'the body must ride with the head' idea is catching on here. Britax and Sunshine Kids have strips that 'rip out' under frontal crash force so that the shoulders do move more with the head, taking lots of force off the neck and chest.
But for the most part, I don't think there really is overwhelming evidence that kids are suffering great neck injury in FF harnessed seats. Yes, there were those in this study, there was also gross misuse and lack of top tethers, which had a lot more to do with the injuries than just the fact of FF harnessed alone.
Given the lack of data proving that older kids are endangered by FF harnessing, I'll keep recommending it and practicing it (I'm not cynical enough to believe that Britax is just out to make a buck off my being sucker enough to buy a HWH harnessed seat, I think they really do think it's the safest option).
I still love this study, I'm posting the link to your blog everywhere