It casts spells for free, which means you can fill your deck with powerful sorceries and instants while also rolling the dice with your opponents
Not only that, Tempest, Dragon Ruler Of Storms can be used as a searcher as well, allowing you to get any Dragon Type Monster from your deck
Farewell This is a card that is neither low CMC, asymmetrical, or instant speed, but man is the versatility on this card powerful
DCIA-L Archives
Via Blogatog Mark Rosewater: I think well see more of both. While this doesnt immediately seem like an endorsement of future Un-set types in mainline sets, reading between the lines does support such a take
Righteous Valkyrie Angels have plenty of powerful payoffs for gaining life, so Righteous Valkyrie is often a valuable piece of the puzzle