I agree that the ruck was designed to allow the helmeted head mobility, but I must disagree with the rest.

The main problem with the ruck (specifically the frame), in my experience, is that it came in one size. This size didn't fit most people. This is one of the reasons I am making my frame adjustable and a new aluminum version will be posted soon, maybe a week or two. It only takes a day or so to make but getting that day is the issue (smile).

I feel the reason solders felt driven into the ground had more to do with the weight they were carrying. I recall carrying a ruck that weighed as much as I did when I was in the army (150+lbs). No ruck is going to be comfortable at that point.

Ironically, the standard size ruck actually fit me pretty well and with a load of 35 pounds is as comfortable as 35 pounds can get. Using the hip belt and chest strap will help with weight transfer, at least it does for me. I am mainly after a weight reduction with my design.

EDIT: I appreciate the comments. It keeps me thinking through and hopefully improving my ideas!