Having read this thread, I have started to use pavise units for storming castles. For some time I have been worried about the number of men I lose due to missile fire from units, arrow towers and wall. Pavise units soak up missiles much better than others. Although casulties are still high, I lose fewer men than when I was using archers or longbowmen. They are slow, so it is even more important to make several breaches and attack in more than one place. I have never used them before because I always play English and longbow men are much better in open battle. I suspect they might also be useful against mounted archers.