When a user with Editor role is given the additional capability of edit users- maybe by using a plugin (like Role Manager), the Editor becomes capable of promoting self to the role of Administrator. This problem was discussed extensively here, and the need for it to be corrected (in the core?) agreed upon.
Anyone know where we stand on this?
I think this is relevant here at mu too because I can see situations where the owner of the site (Admin of the base domain) might want blogs/subdomains to have only Editor roles, but with "edit user" caps.
What I find is that there is some resistance to calling (others might say stereotyping) roles as being superior or inferior, and hence prevent hierarchies. However, in the real world, there is always an Admin, and it is this person who assigns roles, or delegates responsibilities. Not every website is a Wikipedia.com ;)