Diane Mueller discusses the evolution of application development and the transition from Infrastructure as a Service (IaaS) to Platform as a Service (PaaS) in her presentation at FISL 15. She highlights the increased complexity of applications, the rise of DevOps, and the benefits of using OpenShift for streamlined app development, emphasizing automation and collaboration. The document also outlines OpenShift's features, deployment options, and the importance of aligning goals within a company's culture.