CETA and the EU–Vietnam FTA are the first treaties to specify new rules governing the identity, requisite qualifications and tenure of arbitral members, and provide a more extensive review function through a two-tiered investment tribunal system (ITS). These treaties signal a shift towards a more public and judicialized system, akin to that of many national legal systems and the WTO. The ITS creates a permanent first instance Tribunal and an Appeal Tribunal, featuring a pre-selected roster of tribunal members, competent to review the Tribunal’s decisions for errors of law and fact, in addition to Article 52 ICSID Convention grounds—making it a novel ‘one-stop-appellate-shop’. This analysis assesses the operation of, and reasons for, key provisions of the EU’s model by comparing and contrasting the ITS in CETA and the EU–Vietnam FTA. The discussion draws analogies to, and distinctions between, other treaties and relevant jurisprudence which have influenced the negotiators. Among the most striking features of the new EU-led approach to investor-State arbitration is its removal of disputing party involvement in the selection of the tribunal in favour of a standing tribunal appointed by the treaty Parties (which results in a considerable amount of the disputing investor’s autonomy being stripped away), its purported modification of existing arbitral rules in a number of substantial ways, and its short deadlines within which the Tribunal must render final awards.