The new modeling view in Power BI Desktop supports multiple layouts and many features (multi-select) that make designing large models easier. Perspectives should be added to the new modeling view with a 'Manage Perspectives' icon next to the Manage Relationships and Manage Roles icons on the Modeling tab.
In an initial release, the Manage Perspectives dialog should provide the same features as what's available to Analysis Services projects in Visual Studio. For instance, there should be a table with each column representing a distinct perspective and the modeler can quickly choose which tables and individual measures and columns are included or not in a given perspective. Additionally, also like Analysis Services, the modeler should be able to view/evaluate and toggle between the different perspectives to view the user experience.