Systems of systems (SoS) are a hot topic in our "fully connected global world". Our aim is not to provide another definition of what SoS are, but rather to focus on the adequacy of reusing standard system architecting techniques within this approach in order to improve performance, fault detection and safety issues in large-scale coupled systems that definitely qualify as SoS, whatever the definition is. A key issue will be to secure the availability of the services provided by the SoS despite the evolution of the various systems composing the SoS. We will also tackle contracting issues and responsibility transfers, as they should be addressed to ensure the expected behavior of the SoS whilst the various independently contracted systems evolve asynchronously.