While I don't agree with cards being in the cash shop, that is not pay to win. When you have something that will give you a significant advantage that cannot be obtained outside spending real money, then that is pay to win. If they added the ability to buy some 2 and 3 star cards in the cash shop, but those same cards are obtainable in the game (like winning them from an NPC), then that is not pay to win.. that would be "pay to save time".
