This would be absolutely
evil in any rush deck, since you can potentially bust out three hard hitting creatures (dragons) or three of a really important permanent (bonds, shards, hourglasses, etc.) without using the actual quanta of the card in question. I think it's a bit overpowered, except in mono
decks, but other than that, it's interesting.
Since you can play '3' of any card, how would this work with spells like Fire Lance or Rewind? Could you potentially target up to three creatures to rewind back into a deck, or three different targets (player, two creatures, etc.) altogether? I mean, with Rain of Fire, you get to deal 9 damage for the sweet price of 8 aether quanta, but with some of the other spells/permanents, I'm not sure how the mechanics will play out...