The Director in Lync Server 2013 hasn’t changed much from Lync Server 2010 other than being slightly deemphasized by Microsoft. There are still some clear advantages to deploying a Director, but there is no absolute recommendation for every deployment. Each organization will need to make that decision based on its business requirements.
Organizations are most likely to deploy a Director in their Lync Server 2013 environment when they fully understand the benefits of the role. For organizations with multiple internal pools, a Director can improve the environment by acting as a single point of initial authentication and offload that responsibility from the Front End pools. Other businesses might be more inclined to deploy a Director because of the security benefits from an external perspective where it acts as a barrier between the Front End pools and Edge servers.
Either way, deployments including a Director had already been declining in Lync Server 2010, and it’s likely that even fewer new deployments will still include the role.