In my experience most Anaplan implementations focus around a main app where the most users do their work, and most roles are likely only focused on a handful of pages. But as-is they will be faced with the full list of categories of in their dropdown, even if they can't go there or do anything.
I think it would be a major win (for users and model builders) if there was the ability show / hide app categories (and all contained pages) based on a user's role in the model. Here are a few visual examples of how I think this should work:
