Think about this Frankie - if you're going to wrap an injured person in a wool blanket you're either close to help or not far from the trailhead - who carries a wool blanket on any hike of any distance anymore? I carry a cheap $12 wool blanket in the back of my car for picnics, and wrapping up bloody injured people after accidents. They get to keep the blanket if I use it on them.

For wrapping an injured person far from the trailhead use their sleeping bag; for recovery from hypothermia, put one sleeping bag inside another sleeping bag. With zippers you still have better access to potential injuries than wrapped up in a blanket.