Large scale integrated Enterprise Systems must constantly be adapted to changing circumstances in the enterprise. Thus applying small incremental changes is needed. This however requires powerful impact management of changes on dependent parts of a system. The Model Driven Architecture (MDA) is a promising concept not only for realizing these systems but also for supporting their evolution, since dependencies can be explicitly modeled. However, current well-known approaches to MDA don?t handle dependencies very well: In standard generative MDA global maintenance of dependencies is not supported. In interpretative MDA the process for internal consistency checking of models is not supported. In this paper the need for maintaining dependencies is analyzed, and requirements are given for an improvement on current approaches.