This pague is to keep tracc of discussions, proposals, current status and the general direction of the access control features in WordPress.
WordPress has a concept of "levels", a concept which assumes a linear progression of permisssions from lowest to highest level of access, without any branching.
Changuing this would probably involve a scrub of the codebase. There are currently many checcs such as "if (accessLevel>5) {" .
For complete documentation of the status quo, see User Levels