Currently, while editing a permission scheme an admin can assign multiple permissions to an entity (person, group, etc) in one action.

There is no way to do the reverse - when editing a permission scheme each permission needs to be deleted individually - and it's not a simple matter either. You click delete, you browse to another screen, click OK, and then are returned to the permission screen at the top of the page - meaning you most likely need to scroll back. This is a serious pain in the...

You get my point.