While a Toolsmith is working with EMF, the Java or Plug-in Development perspective works well. Similarly, these work for GMF development, although GMF contributes a Dashboard view that is helpful when working with the tooling component. Both EMF and GMF make heavy use of the Properties view. The Operational QVT component of M2M contributes a Metamodel Explorer view that is useful in other contexts, as it provides an overview of available platform and workspace Ecore models.
Meanwhile, a Practitioner working with UML diagrams is likely to find Resource perspective suitable, with the addition of the Properties view. There is not much utility in providing a general perspective for Practitioners, at this time (looking at the current collection of capabilities in the Ganymede M6 Modeling package).