Fairness and empowerment are aspirational concepts in law. The scientific and professional legal community has not convened on their substance and the ways they can be achieved. Therefore, there is an inherent risk that the values they entail become lip services that lack determination and reliability. This section addresses the problem revisiting and expanding the Taxonomy of Legal Usability and User Experience Factors, one of the first attempts to synthetize parametric standards for transaction design. The paper adds factors and criteria that operationalise procedural legitimacy principles for transacting that increase the proactive capacities of contracting activities to prevent and/or resolve disputes. It speaks of transactions as the smallest constitutive units of all exchange relations that allow upgrades, assuming that planning, negotiating and managing contracts, as well as other legally relevant products, services, interactions, processes and systems, will benefit from an integrated epistemological perspective and its institutionalization.