I don't see how thats not fair at all. They subscribed, played enough to buy the unlocks, then why shouldn't they be able to get the unlocks and unsubscribe? If you're that much of an elitist that you feel people who don't pay 15 dollars every month no matter what shouldn't be allowed to play, I think you should find a different game. You're right, free to play really does mean free to play. There's nothing wrong with that, and thus, nothing to fix.
While overall I agree with your post in the regards that they are just using the system as its set up, I really wish people would stop with the insufferable "you're an elitist" meme. All it does is make you look like a whiner and play on the "I'm a victim" mentality.