I prefer that moderators be disjoint from people who have an interest in posting to any topic.
Most clearly I mean:
Moderators should have a distinct log in.
Any action by a moderator should be linked to that moderator's account.
Moderators should NEVER voice anything that might be considered an opinion while using a moderator account.
Short and tart, Pat is a good moderator, Pat should be allowed to speak, give the moderator-Pat a distinct log in.