Even a relatively simple model of two forces attacking and counterattacking presents a large number of alternatives to be studied, Techniques of Systems Analysis notes:
Investigating each one of these and processing them is a major task. It is also a rather useless one because doing things in this way does not lend itself to performing the most important functions of Systems Analysis, such as taking account of uncertainty, doing contingency planning, considering the sensitivity to the model, and most important of all, training one’s own intuition so that one can do a good design job. If these were not enough, there is the final consideration that in anything but a toy problem, this systematic approach would be quite impossible as the number of alternatives is just prohibitive.