I seem to remember reading somewhere that the omission of aiming for the firing of volleys, but just pointing in a general direction, wasnt only because the accuracy was terrible anyway, but also because it softened the moral or psychical impact warfare had on the soldiers, when they didnt aim at a single target, they werent morally responsible for the damage they caused to their fellow man in the same way they would have been if actually having an individual in their sights.

about accuracy, it would seem that if the kill rate of volleys werent so low, it would have been impossible to keep even the most well-drilled of veterans to stay in tight formations under fire.

btw, the tight firing ranks and firing of volleys must be one of the stranger inventions of warfare, it gives you a good punch, but for the punch to do much, your target must also be in a tight formation, and you put your troops in about the only position that inaccurate musket fire can do them much harm.