Could we have a special page that lists all protected pages?
With possibility for narrowing queries by namespace or page title. Maybe
with optional "protected by" filter. And filter by protection level
(semi-/full protected).
It should report protected pages with the effective protection state
(last protection event -- protecting sysop, protection level, date/time,
protection summary).
Currently there is
http://en.wikipedia.org/wiki/Special:Log/protect and
a bot on
en.wikipedia.org compiles
http://en.wikipedia.org/wiki/WP:PP
from that (doing a lot of edits to that page).
As a minor side note it might be worth considering to limit access to
listings of semi-protected templates to sysops (as that could serve as a
recipe for autoconfirmed accounts to vandalize pages via semi-protected
templates).
--Ligulem