When this game came out, I had purchased a copy from just about every retailer so I could get all the bonuses, including lifetime subscription, collectors edition, digital deluxe, amazon, gamestop, atari, steam, etc... Then when the game launched, all the way until last June, I had purchased about everything on the c-store. Since then, actual content in the game has really grinded to a hault. Sure stuff like the academy has been added and first person shooter mode, but the missions are all virtually the same. Most of the new stuff in the game is C-Store related such as ships, costumes, and pets, and the only way to keep up now is to buy, buy, buy.
Anyways, this is where I think a less-is-more approach to the C-Store would benefit both your company and the players more. First off you are selling intangible items that can only be used within this one game. It costs you no more to provide ten of these items as it does to provide a million of these items. The concept of the store within the game is a "microtransaction", and when items cost 1200 cryptic points, that's an $18 purchase with a few spare points. Most toys on a shelf in the physical world don't cost that much, so I hardly say you can consider these microtransactions.
Ultimately what I'm saying, if you all would cut the cost of the cryptic points in half or more, or reduce the cost of the items in half or more, you would more than double the audience buying items from the C-Store. Apps on the droid and apple markets only cost around $1-$2. Music on just about any service is roughly $1-$2. Movies at redbox are $1-$2... Players in your game spend roughly $15/mo or much greater on lifetime subscriptions, only to pay $6-$20 for additional individual items in a game.
Personally if C-Store items cost less than $3 each, I would buy every one you pumped out, even if I didn't use it.