The concept of operations is often assumed when assessing different design variables in a tradespace study for a particular system architecture, The way a system operates, however, has a large effect on its performance, and can often be the only variable through which stakeholders can influence a system after the system is implemented. The concept of pliable system architectures is introduced so that operational variables can be explicitly considered and incorporated into tradespace studies. System transitions can be predicted by pliability, and these transitions can provide insight into other system “ilities” such as changeability, adaptability, flexibility and survivability. Two techniques are introduced in order to demonstrate the usefulness of the pliability concept; (1) a step-by-step process by which operational variables can be identified within a system architecture, and (2) a process by which very large tradespaces can be sampled into a manageable set of system instances that provide maximum insight for the level of effort to model them. As these new concepts and methodologies are new and part of ongoing research, they will need to be tested and validated in future work.