Here's an idea. Why don't just FC say, that "OK guys, we put AO up for crowdfunding. Pay us the costs for a year's operations and we will keep the servers up. You want additional content? Pay up"
This would mean AO could be fully F2P, as long as there are enough pledges from the community to keep the servers up with some maintenance costs (fixing bugs etc)
They could crowdfund new content.
Personally I do not think, that the per-person cost would be higher than what it is now.