The purpose of this paper is to make a plea of reasonableness to the criticism of the investment protection system and to clarify what can legitimately be expected of it. Particular attention is paid to the structure of its design in terms of the objectives it responds to and its position within the fragmentation of public international law. Then, it characterizes the system in its different problems, such as: structural, as a coercive law field, as an alleged threat to the sovereignty of States, and how the system would contribute to consolidating asymmetries. As for the functional problem, the system’s operability and its main limitations are analyzed. Then, it attempts to identify a reasonable solution for the system’s problems, from the perspective of a reform or the application of the opportunities that can be found within it. Finally, conclusions are drawn as to the system’s expectations in the future.