My biggest gripe with card games is always the cost. Otherwise this, like many others TCGs, looks awesome.
I don't actually remember seeing anything about what the cost is going to be, whether it's going to be subcription based or if you have to buy all your cards from the shop with real money. One of the stretch goals was a VIP program (just $4 a month apparently), so I guess it'll be a cash shop for buying new packs and whatnot. It'd be nice if all the cards are possible to obtain with in-game currency though.
As much as I don't like the idea of paying for digital cards as if they were real, I think Cryptozoic will do a really good job with the game. Their board and card games are all a lot of fun, and I really loved the WoW TCG back when I used to play it. I'm seriously considering dropping some money for one of the $65-$120 tiers, just because it seems like there is a lot of bang for your buck. Guess I have 20 days to decide though...