The Group Permissions screen (mode=setting_group_global) could be improved so that it presents as a single page rather than dropdown menu of 3 choices which requires an admin to navigate through a dropdown menu for each of User permissions, Global Moderator permissions and Administrative permissions.
For comparison, look at how Group Forum Permissions (mode=setting_group_local) operates for multiple forums. The single page makes it far easily to manage.
I’ve tried to mock-up a screenshot of how it might look:
Normal people… believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet. – Scott Adams