A couple game developments need to be made to make this practical. Primarily dealing with field activation, the mission editor, and scheduling.
1. Arena setting only allowing takeoff via an active mission.
2. Assigned skins for mission flights. ( not really necessary, but would add a bit to the environment )
3. Automated field activation/de-activation with mission roll/cut-off times.
4. In additon to being able to load a single mission, you could load a stack of missions.
5. CMs would be able to load missions for all sides simultaneously. ( probably a pretty hefty programming effort for this one.. but it simplifies the coordination between sides when setting mission launch times and targets. )
6. Waypoint visibility after mission launches.
Details:
1. This would carryover to snapshots also. No more need to hound people about what to fly or balancing.. just set up the mission and people join. Those that don't join mission don't fly.
2. self explanatory
3. Fields don't need to be activated by CMs. They can just go off automatically.
4. An evenings worth of missions could be preloaded.. perhaps launching every 15 minutes. You log in.. find a mission you want and either join then, or come back when the starting time is closer. Also, a CM could log in, upload a days worth of missions, then leave. No need to be around to babysit the arena. Also, the CMs could tweak the order and composition of a days missions ahead of time.
5. Just to prevent a snafu where launches get out of whack. For instance, if a stack of missions for bombers is out of order with the opposing base defense missions. Wrong targets, for instance. Being able to view all mission stacks at the same time would help keeping them in sync.
6. Minimize confusion as to which flight is going where, keep the waypoints secret until mission launches.
I think the arena would rock, myself.

OP