The complexity of modern engineered systems is growing quickly due to the rapidly evolving nature of today's environment. Current management practices are limited in their structural capacity for coping with such swift transformation, pointing to an urgent need for new approaches in management of complex engineered systems. The model-based approach has emerged as a new promising method to complexity management. However, it is still unclear what role simulation plays in this approach and whether the role differs based on the type of a system under consideration and/or the degree of complexity involved. In this paper, the authors conduct a comparative analysis between the disciplines of System Engineering (SE) and System of Systems Engineering (SoSE), and the significance of simulation in these areas. The paper concludes that simulation represents a major part of modeling of System of Systems (SoS), leading the authors to introduce a new term, Modeling and Simulation Based System of Systems Engineering (M&SBSoSE), to underline the importance of incorporating and integrating simulation into modeling applications in SoSE. It is further also proposed that simulation of SoS should be multi-paradigm to increase the scope of simulation effectiveness in a complex dynamic environment.