
Group A exists
Group B is being made
You click the button next to Group A to base it on group A. Group B starts out with all the abilities Group A has, and you just edit from there. This is helpful if you have eleventy seven mods installed like some of my sites have. That way you don't have to click all 2000 check boxes for things that show up on the front page and hope you didn't miss one.
Another request:
Placement hiding for Groups. This way the groups that you designate (Admins and Moderators usually) would be able to hide where they are on the site. When someone clicks a link they can see which part of the site specific people are on. This may help keep idiots from being morons on the site.