Has anyone tried this on WP3.5 yet? I don't want to blow up my system...
Here's our situation, and why this (if it works) is invaluable. We're running a multisite installation with over 2000 individuals' "ePortfolios" so far -- and growing.
One of our Instructional Designers is tasked with managing the students who are using the system, and so she needs to be able to go into every single blog and review or correct it. But once she had rights on that many blogs, she couldn't log in because the server timed out retrieving her profile -- many thousands of lines in the usermeta table. Not only would her request time out, but the whole server was brought to its knees.
So clearly she needs to be a superadmin, and in fact once I wiped those thousands of lines from the database, she was able to log in immediately.
But just as clearly we don't want her installing or removing plugins.