Besides the three deck packs and the one expansion, there isn't anything else that really can be considered P2W. The foils are cosmetic and the deck unlocks are not necessary. You can access all the cards by completing the solo challenges. The Magic 2013 Gold Game Bundle for 6.79 USD is all the content available for the game at present. Compared to the base game all by itself at 3.39 USD, 3.40 is hardly a "P2W arms race"...

The actual physical trading card game itself though is a P2W arms race absolutely. I threw away hundreds of dollars on it back in the 1990s but the computer adaptation featured here is much more limited in cards available (which prevents the arms race aspect from even being a factor in the current title).