Responding to GenAI technologies, academics press for PLD that informs pedagogical practice and policy development. However, insufficient critical evaluation of whose knowledge informs this and its underlying complexity has resulted in excessively reductive offerings that either champion specific tools or advocate for their prohibition. Engaging with critically complex perspectives provides an opportunity to deepen discourse through untapped funds of knowledge, while considering PLD's broader role in policy and institutional development. English for Academic Purposes (EAP) lecturers are typically peripheral within universities, positioned as a remedial or technical service who 'fix' academic integrity and student language development issues. GenAI disruption has created a heightened demand for language expertise, offering an opportunity for EAP lecturers to advocate for the critical complexity underpinning their funds of knowledge. Using Legitimation Code Theory (LCT) within a Delphi study with senior EAP academics, we argue that engaging with critical complexity can empower institutionally marginalised expertise. The panel established design principles and actionable measures to (i) move beyond individualistic PLD and (ii) formalise the voicing and valuing of diverse expertise through collaboration across institutional hierarchies. Taken together, these offer ways to leverage epistemic relations to disrupt entrenched power structures through transformative PLD and thus catalyse institutional change.