>>856985True and true, I guess ventile does work at temperatures higher than felted wool does and is not actually more expensive.
As for windproofness, the more felted it is, the higher the resistance to wind. Most are not actually totally windproof like good cotton, but the peacoat may well have been barely felted or loosely woven wool.
Regarding water... hard to say. Wool certainly deals with sweat better than cotton. The loose structure preserves breathability even when wet and allows for good evaporation. When it comes to rain, it depends on shittons of factors like the rain pattern, drying times, movement, type of wool (lanolin content especially). Most water would be shed, but eventually it gets wet and insulation is correspondingly lost.
If we look at historical uses, basically everyone until WWII wore some kind of wool in temperate or colder climate. For extended situations outdoors, people would almost always have some kind of poncho, cape, etc. These were traditionally wool (to double as blanket and/or because of lack of other materials) or cotton as in the zeltbahn or plash-palatka of 20th century armies. The wool jacket or coat would protect against small showers and the cape against heavy rain.
Ventile was only invented during the war, and everyone moved to rubber, chemical impregnations and eventually goretex afterwards. So we don't know from real world examples wether it would have replaced wool. The british love for ventile does suggest it would work in cool wet situations. That's rather weak evidence from mostly leisurely use though (yeah I know it was used for exposure suits, but that's an entirely different thing.) I've seen comments on "eta-proof", which is basically the same as ventile. People mostly say that it works ok for short term rain protection, but does get wet and cold eventually (indeed just like wool...)
