Weak S makes harder to study and control your body in physical activity. Not all occupations have strong requirements for this. Also N types have better "feeling" where an activity to use with better result, what compensates partly. With weapons development a need in physical efforts becomes lesser and lesser.
N types are predisposed to make better decisions, which take into account more factors. They evaluate situations quicker. So they are easier to become good officiers. While S types are some better where direct physical efforts are needed what is more common for lower ranks and lesser advanced weapons.

Ne types have the most aversion to a violence. To direct and near violence. They'll shoot in you by a rocket without problems. Also they least like direct enforcing what is common in army, but more for lower ranks where S types fit better anyway.

Ne types issues could be serious problem in manual weapons of the past. Since fire weapons age, except sniping, this should not be. In today times stay as a problem physical harm, hunger, cold, fatigue, etc. problems of wars, what Ne types accept harder. To be in low ranks is hard for them. To be officers - ok.