Finite state machines and their extensions are widely used for system modeling and analysis. Often, the models themselves do not provide much insight into critical system areas which need to be observed (or monitored) for effective control. The issue is mostly left to the discretion of the development team which often has limited domain knowledge. In this paper, an effective method to identify necessary critical system areas that need to be observed and those areas that lead example to the identification of varying levels of control in a design model are discussed. Also, the applicability of this method in differentiating and choosing between two similar system designs is discussed. Extended Statecharts (ESCs) that exploit the XOR configuration of Statecharts for system failure modeling are used for developing the high level system model. The ESC model is subsequently transformed into a high level Petri net model and Petri net analysis techniques are used for the identification of critical system areas for observation and control as well as to differentiate between nearly identical ESC system models.