Several years ago, first generation model driven engineering (MDE) tools focused on generating code from high-level platform-independent abstract descriptions. Since then, the target scope of MDE has much broadened and now addresses for example testing, verification, measurement, tool interoperability, software evolution, and many more hard issues in software engineering. In this paper we study the applicability of MDE to another difficult problem: the management of complex systems. We show how the basic properties of MDE may be of significant help in this context and we characterize and extend MDE by the concept of a "megamodel", i.e. a model which elements may themselves be models. We sketch the basic characteristics of a tool for handling megamodels and we apply it to the example of the Eclipse.org ecosystem, chosen here as a representative illustration of a complex system. The paper finally discusses how the proposed original approach and tools may impact the construction and maintenance of computer based complex systems.