What is the method set in place which monitors the hosts from abusing the "off topic" choice? It's not to say that hosts will abuse their powers or that anyone did in your or any case so far, but that there HAS to be something in place as a check to balance out their power over the group.
Sitting here I was thinking and trying to figure out a way to do that. The only thing I can come up with is a recommendation based system. It would be very easy to create in theory. Attach to the hosts a "recommendation function". The host with the most recommendations gets the #1 host position... and downward from there. And it's ongoing and permanent. If a group member later chooses that he/she/etc. doesn't like the host anymore because of a decision... they have the power to take away their recommendation thus potentially lowering the host's rank or perhaps if below a certain number... removing them entirely as a host. It would all be automated and the Admins never have to touch it again. The group will be run by the elected hosts perpetually.
Well that's the best I've got. What do you think?