Autonomy is expected to cause significant changes to the Maritime Traffic System (MTS). The Vessel Traffic Services (VTS) is a control system in the MTS and will be affected by new interactions caused by autonomy. The paper proposes a proactive approach in discussing the future VTS. The paper renders the historical development of socio-technical systems theory and argues for systemic evaluation of internal and external consequences of changes in the design of the future VTS. A democratic process to involve people from the various levels of the VTS organisation with different competencies is suggested. To evaluate the consequences of change, a systemic internal and external approach is suggested. For discussing internal consequences, a levelled socio-technical systems model is adapted and applied. External consequences are suggested to be discussed by applying design principles of system-of-systems to understand the interplay between VTS and the MTS.