I've gone ahead and enabled the semi-protection level for all of our wikis.
A total of 16 had already explicitly requested it over the last couple months,
and I haven't heard from any site asking to keep the option on.
Unless it's actually used by the admins on a given site, there's no change in
behavior; it's just a middle-level option now available between unprotected and
-- brion vibber (brion @ pobox.com)