Between the elimination of HTH, and the current settings in the open arenas, it is impractical to arrange private events for small groups. There are plenty of instances where groups of players would like to get together in an environment where they are not subject to griefing. These instances do not always rise to the level of trying to vie for an SEA time slot that does not conflict with its normal uses, and still align with a time that both a CM and attendees can make.
One versatile solution would be some sort of player initiated duel mode. The Air Warrior example comes to mind. In that example, when two players entered duel mode and spawned, they were effectively in a parallel virtual reality. They could not see or interact with others in the arena beyond text, nor could the rest of the arena see or interact with them. They were immune to griefing. Furthermore if several players entered duel mode with one individual, all those players could see and engage each other. I know this instance had been frequently used in AW for tournaments, and private koths. Understandably, the AH game architecture may not be conducive to doing something exactly like the AW example, but surely there is some way to enable players to initiate an instance that will exclude unwanted interference in at least the dueling arena?
Another option that comes to mind is enabling a form of HTH with a higher roster cap that would be available to paying subscribers.
