From a professionalism stand point, I think the gantt chart and team expectations are important, but I believe the risk management deliverables and the combined effort to identify input requirements. In my opinion these two things really get the ball rolling and essentially gate all other downstream activities until this is well defined. They set the scope for the project and define what activities will need to be completed for verification and validation. In the event that the risk management and input requirements are not well define, I believe there will be major gaps in the device design, they will have trouble proving the safety and efficacy of the device, and they might blow the project time line because of repeating work to close those gaps.