I love what I see.
New faction (exile), new card type (artifact), and new mechanics (preemptive) in addition to deepening existing factions are just great way to show this game will continue to evolve rather than just become variation of themes.
Though one thing I am potentially concerned when this games goes live. It may be better to call whatever the set of card available at that point as the first set. This is an extreme example, but there was a game called Carte, which was released in Korea almost 1 year before the rest of world saw the game. So there were already like 8 sets (they called episodes) by the time the game became available in US. Too many cards for starting left a bad first impression but what worth was you are already 8 sets behind... So for now I think it's great to call Set names for beta players but when the game officially launches, perhaps conceptually new starter should probably feel like they are there from the beginning. What do you all think?