Surprisingly, I don't see any replies to this post (unless my "view" is wrong or something). I was recently told by SmarterTools that this sorting feature, as well as the system admin's domain-level disk usage reports (the ones that let you drill down to user level) were removed due to "performance issues". Personally I never saw any performance issues when using either of these features and would really like to have them back. Perhaps instead of removing them altogether, ST could put them back, disabled by default, and give system admins the option of enabling them. I can't imagine such an option would be that difficult to implement.
Have a good one!
Centennial, CO. U.S.A.