and not meaning to point anyone with a stick, some of these groups have distinct personalities and challenges that others don't.
Controversial to me would be a group that has extremes and would need to take those into consideration - ex, Gun Control, Religion/Theology, Israel/Palestine, 911 (Creative Theories).
Protected (only one viewpoint) are safe haven forums so members who want to gather with like minded members only have a place to congregate away from controversy - ex. Barack Obama, LGBT
Open Debate would be the more generic forums where people of all stripes of interpretation are welcome and the group as a whole enjoys reading open discussions
That said, the TOS of the message board is the oversight and TOS violations trump any group dynamics.
I agree that in the Open Debate areas, hosting is not nearly an issue, but there are things a host can do that the Jury cannot like ban disrupters from their group, open close and pin threads, etc..., so from a maintenance perspective, is a good idea - noting that the only person who can delete a post is the person who posted it (not juries and not hosts).
Lastly, each group can have 20 hosts. Skinner will only appoint one host per group - after that it is up to the group and its hosts to add other hosts to the list. In order to kick that off, one has to be appointed then it is up to the group what to do from there.