Getting shot to bits is pretty realistic for the time period. In real life, regimental battalions would stand in front of each other as well, fire a few volleys leaving lots of casualties as a result. After that, they would usually do a mass charge to scare the enemy lines forcing them to retreat.
French Marshal Ney's "Military Studies - Instructions for the Troops composing the Left Corps" in the section "Observations upon different modes of firing" on pages 99-101: "The firing of 2 ranks, or file firing, is, with the exception of a very few movements, absolutely the only kind of firing which offers much greater advantages to infantry... Most infantry officers must have remarked the almost insurmountable difficulty they find in stopping file-firing during the battle, after it has once begun, especially when the enemy is well within shot; and this firing, in spite of the command given by the field officers, resembles general discharges.
It would be better, therefore, after the two first ranks have fired, to charge boldly with the bayonet, and by an act of vigor force the enemy to retreat. The German soldier, formed by the severest discipline, is cooler than any other. Under such circumstances, he would, in the end, obtain the advantage in this kind of firing, if it lasted long... These observations are of a nature to urge colonels... to prepare and drill their men to attacks by main strength...a French commander ought never to hesitate in marching against the enemy with the bayonet if the ground is at all adapted to a charge in line with one or more battalions at a time." (This is interesting that although Ney recommended two ranks, in 1813 at Leipzig he formed his own infantry on 3 ranks.)
I think that if you would like to play NW in a realistic way, every regiment should make 2 or 3 lines regarding the attendance the regiments have.