Roles for collaborators and limited file access

Sometimes people want to help me with my projects, maybe there’s a tedious big array that needs to be filled with data, maybe its tweaking css. The issue is, at the moment the project roles are all or nothing, you either can’t view the project at all (it is private) or you can do anything you want including viewing the api keys and removing the owner from his own project. Perhaps there should be more roles with limited access, e.g. i can say that a person can only edit these two files and nothing else, or maybe edit one file and view other three.