Some "questions" on metas really are announcements which ought to be pinned on top of meta question listsings for wider attention (or at least frequently bumped by Mr. Community).
As others have said in the comments, I think this would pollute the questions list.
Have a ♦-only tag called announcement for such questions and have a widget on the home page (similar to the faq one):
We do have the [featured] moderator tag now on per-site metas.
It is not currently used to pin, but it does affect the meta house ad on the parent site.