There are a few things which help to mitigate the risks associated with Project Server implementation initiatives:
-Mitigate the risk of reduced participation by ensuring all relevant stakeholders are involved upfront during the solution design.
-Establish a communication plan to help ensure involvement of relevant stakeholders.
-Identify key people to champion the process and tool.
-Select an acceptable deployment approach (i.e. Phased, Co-location, Role, etc.).
-Use early adopters to test the solution.