If the upcoming version already has this, forgive me (I haven't seen the admin end yet).
It'd be extremely handy for moderators to be able to move posts and/or threads to an invisible board, a sort of purgatory. So, for example, a junior admin can await ruling from senior admin while tucking the suspicious thread out of view, etc, etc.
Also (again, if the program already does this, never mind), it'd be great to have a non-public board for admins/moderators only, to discuss moderating issues, etc.