I would not choose a wool blanket over a good sleeping bag for backpacking, but I would never discount the effectiveness of a good wool blanket. When I was a young infantryman (long, long ago) we did not get issued rucksacks. We had our Load Bearing Equipment (LBE) with a butt pack. We did get issued the old, heavy mummy sleeping bag. The problem was that the sleeping bag could not be effectively carried attached to the LBE. What many of us did was construct a modular, layered package for sleeping. If you start from the ground and move toward the body, it consisted of a poncho, Space Blanket, wool blanket and then a poncho liner. This could be rolled and attached much like you see in old WW I movies or even like a Civil War bedroll, draped over one shoulder. You could also roll other things up in it for easier packing. Our commander's concept was that rucksacks get packed full, and that makes it heavy and slows the soldier down. He wanted us moving as light as possible. While not the warmest or most comfortable, it did work for even near zero temperatures. Not a first choice, but an option. Of course, with the newer technologies in sleeping bags, this bedroll would actually be heavier.