Platform-based design faces an essential tension: it wants to reuse previous designs to leverage IP; but new designs must necessarily include work that is not complete or well-characterized. Synthesis and analysis methods are therefore important elements in platform-based design methodologies. This paper describes two aspects of this problem. First, we consider the first-generation dilemma, in which we must use additional analysis in order to create the first generation of a platform. Second, we describe a synthesis method that creates accelerators for platforms whose clock periods have been optimized for the system characteristics.