"I haven't had a bath in weeks, so as one of the "unwashed", let me ask a question: how are you guys so sure I am not having fun?"
That's kind of my point, Kieran; in an bellybutton backwards way....
The MA should be the most fun, for the most people, always; or at least, that's my take on it.
Out of that "most people" (aka the unwashed

), only a realatively small proportion would be dissatisfied/motivated enough to try something else....
At the moment, it's seems to be about 10-20%, very rarely (if ever)reaching 25% of the logged on player base.
At that rate, to get a really active CT population of, say, 50? you'd need around 300 -500 people logged on on average.
Which is something I think would be great!
So here's to overfull arena bursting at the seams, I reckon that's a better bet to get a full CT than closing the MA down at pre determined times, as has been earlier suggested. Fill that MA up! Fill it up I say!, then we'll see more posts like this thread starter, and we'll be able to say go to the CT/TOD/Snapshoot/Scenario and have a very full, and very diverse AH community.