The 2/3 majority is essential because without it, a clique of moderators on TalkBoard (already holding a simple majority) would be able to push their agenda through without paying any heed to the views of the other elected members representing the general userbase.
I'd be happy to support a lowering of the 2/3rd standard to a simple majority provided TalkBoard were to amend the guidelines to ensure that the number of moderators permitted to serve concurrently as TalkBoard members did not exceed 50%.