Developing a relational platform doesn't sacrifice any of PowerPoint's normal functionality. If desired, you can keep templates and themes consistent throughout an entire network. Doing so is not especially recommended. That much consistency usually leads to monotony. Focus more on providing quality visual content and media, such as pictures that cover the entire screen or animations that actually accomplish meaningful purposes. Master slides are quite useful in relational design. In some cases they fulfill their traditional role of providing visual consistency but are even more beneficial for simplifying complex navigational structures.