The Monday Avacyn Restored previews continue:
Riddle Me This: Is it worth jamming four copies of Temporary Mastery into any deck, even if that deck didn't run any type of Brainstorm or Ponder effect at all? I ask this because unlike Thunderous Wrath and Banishing stroke, this Miracle card actually replaces itself. While those other Miracles can end up being dead cards in your hand for an extended period of time, Temporary Mastery can actually gain that card advantage back. I don't know if I'm saying this clearly...
Imagine you draw your opening 7 cards and find a Temporary Mastery in your hand. You basically have no chance of casting it the entire game and are now playing as if you have a hand of 6. But then on your 2nd turn, you top deck another copy of Temporary Miracle, take an extra turn, drawing an additional card in the process. This means you gain that lost card back on top of everything else you get to do on your extra turn.
(Don't get me started about eternal formats where Force of Will exists and you can just pitch extra Temporary Masteries for the counter.)
I think the possibilities are endless for reasons I just described above. I don't even know where to start. Actually, I think you start by jamming four copies of this into any deck that uses blue and keep on testing to see if it's worth it. I wouldn't even be able to tell you if it's good or not without testing first.