As a Confluence Administrator I do not want to be responsible for managing the membership of groups that are assigned for access to separate spaces.  I would prefer that those Space Admins manage membership in the group or groups that have rights in their space. 

I realize that a Space Admin can add individual users to their space.  However, they must then assign all the separate rights.  It is easier if we define rights by group (eg spaceviewgroup vs spaceeditgroup) and then assign users to the appropriate group.