Mission Channel being ".radio 4 6" I believe
Most players do not know about this channel, so it is rarely used. This is possibly because most players that join missions are still newer players that don't know everything about AH yet.
Perhaps a button to be added to the mission pages, where a player can click "automaticlly tune to mission channel"
OTOH, some players like to join the mission, but not in one of the pre-determined mission vehicles, or just as a gunner, and therefore not in any assigned vehicle.
When this happens, the mission channel is no good, because not everyone participating in the mission objectives can tune to it.
The mission editor is nice, but being the mission planner is sometimes a big pain in the butt, with people asking stuff like
"why no Spit 16 in the mission?"
"why DTs and not 500lb bombs?"
"Can you add plane X and then I'll join the mission"
"How come you only have 50% fuel selected?"
"Why do you have 75% fuel, that's too much?"
"Don't add the rockets to the Mossie, the rails make it fly bad"
Blah, blah, blah....