In Workflow, admins can specify status changes for a tracker. These are true/false transitions Like:
New -> Doing
Doing -> Done

My proposal is to specify the kind of transition using icons:

• Forward icon: transition going forward (legacy behaviour)
• Backward icon: transition going backwards
• Undefined icon: unknown transition (and resolve conflicts)
• End icon: transition to an end state

Thus, when you use the dropdown menu to change status, it could show if the change is going forward, backward, etc according to your workflow. This would help users to know if a status change makes the issue closer to completion:

New (->) Doing
Doing (->o) Done
Doing (<-) New

The icon should be shown in dropdowns in the issue menus (edit and context).
In Admin > Workflow, clicking in a status change should cycle through the icons.
Role conflicts (forward in one role, backward in another) should use the undefined icon.