Redmine Administrator is limited by roles, memberships and workflows
User leaves company. All their issues that are open and ones that were closed in last 2 weeks need to be reassigned with a custom status. As administrator I try to change status and I am told I don't have permissions. Now I have to add myself to project, only to change status, and then remove myself from project. And I have to do that many times from many different projects.
For Redmine administrators allow all actions, give warning if they do something that is outside of typical use (like changing status outside of typical workflow).