If a leader is killed then a substitute leader is used. This leads to some interesting situations. This promotion is performed by flipping the counter over. In some cases, the substitute's rating is better than the original, but not often. So as the ratings fall due to losses there is a gradual degradation of efficiency.
Losses have another effect on efficiency.
Each side in a scenario has a preservation level. As the unit takes loses its preservation points accumulate. When the preservation level is exceeded, the unit becomes demoralized. Basically, individual instincts start to dominate the good of the group. These are the core of the basic rules, and hopefully a general style of play becomes apparent.