The View-Variables and View-Collections screens are useful when trying to locate the point of initialization and setting of variables and collections. It would be great if we could rename all instances of a particular variable or collection from these screens.
I've found while building apps that my initial naming scheme changes halfway through the development process. This can be due to new features, rethinking of the app architecture, or changes to data flow. This is a typical feature in software development and it would be great if PowerApps would support central refactoring of variables and collections.