You don't think some sort of Micro transactions would help that issue? It could be anything from purchasing skins to perks.
I'd never say never to that. There do seem to be some decent F2P models out there, but they are the exception.
Over the last 2-3 months I put some 80 hours into Mechwarrior Online. Their system was actually rather interesting but it would be a pretty radical change. Not sure how successful it is for them either. The way it works is you have maybe 20% of the rides available for free from one week to the next. This way you don't really feel shorted because you still have a pretty decent selection of rides. It encourages people to try new rides and gets them hooked on the ones they like. Using these free "mechs" you begin grinding out currency (similar to perk points) and can purchase a ride that you can use all the time and customize to your liking with colors/skins that you also purchase for in-game or real currency.
New players start out with a mech bay (hangar) that can hold 4 mechs. Once you purchase your first 4 rides, the only way you can purchase additional mechs is to spend $1.50 worth of real money for an additional mech bay slot to park the darn thing. This struck me as pretty fair overall.
Applied to AH, this would mean all rides would have to have a cost assigned to them. (Personally, I'd make the cost directly proportional to use in the previous tour, likely making the P-51D the most expensive ride in the game for in-game currency and giving players incentive to buy unique rides that don't see much use) A new player would be greeted with an income bonus of some kind his first couple weeks to ensure he has enough currency to buy a few rides. If he doesn't want to purchase one for real or in-game currency he can fall back on the 25 free to play rides for that week. (Also, purchased rides have a slight income boost, giving you incentive to fly planes you own) If said new player wanted to unlock every ride in the game at the cost of $1.50 each beyond the first 4 hangar slots, it would cost him $180 bucks, equivalent to a 1yr sub. That is before the 25 cent skin downloads etc. What happens once the player drops the $200 bucks his first year? He plays for free. That may seem like a big loss when looking at long-term players who have dropped $1,800 bucks on AH subs over the last decade, but at this point what AH needs is new players. People who pay $180/yr to play a game year after year are the exception, not the norm.
In terms of transitioning: All players would be allowed to subscribe to a $15/mo. premium acct with full access to all rides (like we have now). Those that don't opt in have access to the weekly rotation of trial rides and can play/pay their way through an awesome, fun, non-p2w game. Existing players who opt out of their existing subs would be able to keep their existing perks and cash them in for currency at their leisure, ensuring they are treated well during the transition.