You should always have at least two people with full admin permissions. Only one = potential server collapse if that person deregisters and refuses to associate with any game activity and/or actually dies.
Having more people as admins opens things up to other problems though, like that time you nuked greedoland by banning everyone.
Yeah, you don't need the full staff team of 6 people that we had for Greedoland 2.5. Chair, Vice Chair, and perhaps the Secretary is sufficient. The biggest thing is that you shouldn't have to start a whole new server if the Chair just randomly leaves.