We propose a framework model to facilitate the prototyping and refinement of Massively Multi-player Online Games (MMOG), when included in the appropriate development environment. This work-in-progress report is motivated by observations made in the video game industry about the industrial process of designing such a demanding application, and based upon the technical know-how in that domain. A major benefit of the development environment based on this framework would be to validate game-design interactions when confronted with technical feasibility. A further benefit of this tool would be to assist the rest of the development process: for a spiral life-cycle style process, the tool could provide some interesting ways for analyzing the performance of more and more accurate prototypes at each stage of the development.