I keep getting into argument over at MMOC (yeah, yeah, I know...) about the whole "pay to win" thing.
It's my belief that the matchmaking system will prevent F2P players using only starter decks or basic cards from regularly going up against P2W players that have bought a hundred packs and have a deck full of Epics and Legendaries.
Think about it.. if the deck really makes a person "better" (which, based on what I've seen, it doesn't), then obviously that person is very quickly going to be placed in a different bracket than you, and you'll end up playing against people more or less at the same level you are. Whoda thunk it? MATCHMAKING.
I keep seeing people saying that if you don't pay for card packs, that you'll end up "behind the curve" and you'll be playing against people that will stomp you up and down, you'll lose exactly 100% of the time, therefore you won't have fun, therefore the game suxx, etc.
That said, I've seen players with really good cards get stomped, and I've seen players using only starter cards (custom decks, but still built with only basic starter cards, and a few packs won in-game, which everyone gets early on), but playing those cards well, and they stomp on the other person with "better" cards. Just in the videos I've watched, I've seen people throw down epic cards and trash talk about how much they're going to wreck the next turn, and then all those fancy cards are utterly destroyed before they ever get a chance to play them, because the other player had a couple buffs and board wipes tucked away for moments just like that.
I think better cards will let you have more fun, by doing fun things, but it's still going to come down to how you play them, not just their presence in your deck.
But, at the end of the day... they've got a Leeroy Jenkins card. And it plays pretty much like you'd expect: Leeroy is 6/2 with Charge, and summons two 1/1 whelps... for your opponent. That makes it okay in my book.