>>13610761. You don't wear it while stalking (which germans barely do anyway, it's mostly sitting and waiting for the animal to come by either by itself or driven by someone else).
2. It doesn't flop around because it is more like a wide coat than a poncho. These wool cloaks were also very common among mountainfolk, far longer so than in the lowlands.
3. Wool has the great advantage over synthethics that it doesn't make any noise. There are in fact woolen garments with synthetic filling to make use of that. Yes it weighs a little more, but 1kg of wool absolutely pales compared to 100 kg of hog. A german hunter will not walk long distances anyway because he simply does not have to (some are literally driving their cars into a 100 metres of their stands... not /out/ even by german standards).
Historically speaking, wool was the only fabric to provide warmth and water protection - these cloaks could be found almost identically since antiquity. In modern days, most hunters actually don't have one - they have roofed stands, fleece and synthethic insulation.