Located at the meeting point between telecom operators and over-the-top service providers, metro networks are particularly well suited for the introduction of radical acceleration of dynamics in the optical networks, leveraging elastic building blocks such as transponders and optical nodes. In this paper, we review innovative solutions which could be used to address some of the challenges of metro networks in the short-medium term (e.g., 2-5 years from now). In particular, we discuss the most valuable application scenarios for elastic optical networking. We then highlight a few features of next generation metro networks and outline the main road toward this next generation with network experiments and associated use cases.