This page is to keep track 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 permissions from lowest to highest level of access, without any branching.
Changing this would probably involve a scrub of the codebase. There are currently many checks such as "if (accessLevel>5) {".
For complete documentation of the status quo, see User Levels