I think it doesn't hurt if there are several different tools in one category. Not all tools have the same features. However, if a tool is too simple it doesn't really make sense adding it just for the sake of completeness.
Leos, thanks for the creating this wiki doc. I changed the title to "free admin tools." I suggest to remove all tools that are not free because otherwise you invite all vendors to add their own tools to the list. Wiki docs can be edited by all 4sysops members.