Over time I've found that it's a waste of effort trying to rigidly structure your cases by anything other than Project and responsibility (Area).
Just get the cases into FogBugz under the right project and area with a good title.
So, the Project is whatever the product or business project is that you're working on.
The areas should be things like UI, Code, Docs, Data Migration, the kinds of things that people have different responsibilities and/or abilities in.
Then title your cases for easy management and searching, keeping the scope of the case to a few hours if possible, certainly no more than a couple of days.
So, from your example it could be as simple as...
- Add Role
- View Role
- Update Role
- Delete Role?
- List Roles
- Add User
- View User
- Update User
- Delete User
- List Users
- Add dependency checks to delete role.
To be honest, even the above is probably a little over-board, you'd probably get away with:
- User Role add/view/update/delete/list
- User add/view/update/delete/list
The simpler you make it, and more trust you put in your devs, the less hampered your devs will feel and more likely to just get on with it.