The IIBA webinar, led by expert Ln Mishra, focuses on the challenges of gathering critical non-functional requirements (NFRs) in software development, especially in agile environments, and discusses best practices to avoid missing these requirements. Critical requirements are defined as those that, if overlooked, can lead to major project impacts, including potentially its cancellation. The session emphasizes the importance of stakeholder awareness and the development of comprehensive lists and templates for capturing both functional and non-functional requirements.