In these times of high tech and internetz, commanders can keep talking even after they died. => There is no actual tactical advantage of killing him, he will turn into a ghost and call his frightened soldiers to pick up their weapons again and fight untill he rises from his grave.
However, this might actually add some fun roleplay to the game. Maybe give the option for hero characters to give their char a different set of equipment? This way they can either choose some shiny ass armor so they can ride around on a plated charger in the most beautiful heraldic/plate armor or they can choose to blend in with the other troops and be a more down to earth leader figure (one that is just another soldier and fights the enemy side by side with his mates).
Killing the commander might still not give any bonus/advantage, but you can call out on ts or caps lock in global chat that you got that fucker
