One thing that my brilliant move to simplify the WPMU backend for teachers didn’t take into account was performance. The site has been suffering a bit since the upgrade, and since so many things changed at once I hardly know where to start looking for problems.
Jason over at wpmu.org posted an idea, a real head-slapper, that I think will help: Don’t run plugins intended to modify the admin area on every page. He probably wasn’t the first to come up with this concept, but he had a nice premade plugin that I could download and so he wins. Since one of the major changes I made was to add these new admin-only plugins, I’m going to keep my fingers crossed that this change solves our performance problems.