What if they let people play for free and only charged for what are currently the "free" updates? That would be really interesting. It could basically cost the same as paying $15/month (or less) and would be an interesting way to charge for additional content -- almost an 'episodic' approach to MMO gaming. Sort of like Guild Wars, but with more frequent, mini-expansions for a lower cost. For example, imagine if Book XX cost $15, but you didn't have to have it to play. Players with lower level characters wouldn't need it, but once they hit that point, they could spring $20 and explore the new content. After a few of these come out, Turbine could bundle the older ones and sell them at a lower price - OR - every time a boxed expansion comes out they could bundle all of the previous books on the disc. Sort of like Guild Wars, but with more frequent content updates.

This would play well with a console version as the substantial updates every few months would be optional, yet the game would remain free to play barring any existing online subscription for the system itself (e.g. Xbox Live). This type of model would also work with the lifetime subscribers as they would be given access to the paid updates as soon as they become available -- or at least that is what I hope they do if such a system is implemented (I am a lifetime subscriber, lol).

This is just one idea, I have no indication that they are doing this. Just a thought. Personally, I would like this method of payment because I often take breaks from MMOs and it would be great to feel like my money went toward actual content instead of just dumping it into a monthly subscription fee. Then again, I have a lifetime subscription so I'll sit back and see where that takes me!