Scaredgirl, I know that you and I agree. I wasn't freaking out or anything, I just felt like this discussion was getting a little heated when it really doesn't need to be. And when I read your posts, I saw pretty much the same arguments over and over, largely because of the similarity of others' comments.
I think the OP was arguing that it takes no time at all in getting whatever it is that you need in this game, suggesting that there is no inherent challenge directed to players in acquiring cards or upgrades other than putting in time. Increasing the cost of upgraded cards would only increase the time it takes to get them and would not increase the challenge of the game. I don't support this at all. The argument that more time = more of a challenge is false, and is the reason why I haven't really invested much in this debate, as there really is nothing to argue about within the confines of the OP.
If you really feel this game needs a change to keep players - both new and veteran - interested, I think it is safe to say that a drastic change in the AI, a new level of play, a complete redux of the PvP system, many more new cards, or any combination of these would add sufficient challenge and content to keep players interested.