I liked the way we did it in AW. They had a "ready room" that the mission leader would create. The leader would then load up a saved mission... at one time I had close to 50 different ones, or would plan out a mission using the tools available which included a map that you could map out all the waypoints for each wing. As a participant in the mission you could choose to see only your mission path, or any/all of the others.
Once the mission was up players could request permission to enter the ready room. If they mission leader didn't "know" or want the player in he could deny that player entry. "new" player got in by being recommended by other players who could get in the ready room. If another player vouched for him, you let them in and give them a shot. If a player got the reputation of being an prettythang then they didn't get into too many missions.
Mission briefings were "private" and easy to do because you had all your mission guys in the "room" with out outside distractions. Once you rolled the waypoints showed everyone "where" to go, the briefings told everyone "what" to do, much less chaos for the leader. Also, it seemed a bit more immersive than what we have today, so that made it that much more fun.
