There are Foundation-level issues that need to be kept
to some degree
of confidence. Although, frankly, I think "all admins" is too broad
of a level to release most of those items because, quite frankly, we
have a great many untrustworthy admins.
Trustworthy or not there are hundreds of active admins. Anything discussed
in an Internet forum with hundreds of people is very close to being public
information.
Most of the regulars on wikien-l are old hands anyhow. I'm not sure if
you'd get a substantially different forum by creating an admin-only list.
In any case it would mean a substantial change in what it means to be an
administrator. This should be well advertised and discussed before it
happens.
Regards,
Haukur