Bayonets weren't used like they were in the Napoleonic Era. They were considered a fear weapon. Most men would rather club their enemies, which would do a lot more damage, and often times not kill the guy they hit, which is what the point was. Mind you, the Civil War was fought "Brother vs. Brother." Friends fought each other, family fought each other, communities fought each other. Most men didn't want the other to be killed. Using the gun as a club could incapacitate their foe, rather then kill them.
However, bayonets were used to scare off foes. A large bayonet charge can make a whole regiment run away and shatter with little to no losses. Especially when the Rebels did it. The yells and screams were more than enough to cause Federal boys to turn tail and run for their lives. Add a bayonet, and you have a wall of death that can cause anyone to run, maybe even the most elite of units.
What I mean by all of this: I do sincerely hope that bayonets will not be permanently fixed like they are in Napoleonic Wars. Rather, they should be equipped when a person wants to use them. And, to balance the use of a bayonet, accuracy can be slight decreased in turn for better melee efficiency.
I think it was nice in N&S how you had to attach bayonets yourself it made the game more realistic for me and more fun for when we are ambushed without bayonets attached.
This is precisely the point.