In this work, we raise three critical questions that must be investigated to ameliorate composability ofvirtual simulation models and to enable adoption of systematic and stringent real-time techniques toenable more scalable simulation models for virtual and constructive simulation. The real-time techniquesin question enable us to separate between policies and mechanisms and, thus, the simulation engine candecide dynamically how to run the simulation given the existing resources (e.g., processor) and the goalsof the simulation (e.g., sufficient fidelity in terms of timing and accuracy). The three critical questionsare: (i) how to design efficient and effective algorithms for making dynamic simulation model designdecisions during simulation; (ii) how to map simulation entities (e.g., agents) into (real-time) tasks; and(iii) how to enable a divide and conquer approach to validating simulation models.