Here's what I see with Aethermage's Touch:
"Reveal the top four cards of your library. You may put a creature card from among them...(blah blah)...[into] its owner's hand"
It's an expensive, limited version of Impulse. Yes, it has potential to be more, but 1) the creature doesn't gain haste, and 2) it might miss. I think if you build a deck around the card, you are going to end up with a decent amount of unplayable cards.
It doesn't have the same problem that some of these cards have, where you simply have to leave out utility cards to avoid getting those instead.
It does have the additional flexibility of potentially blocking. If you are lucky, your creature comes back to your hand. If you are very lucky, theirs dies. A surprise defender can't be all bad, but don't necessarily expect to get anything that you really want to block with.
Would I play this card in limited? Certainly. Might even try to build a constructed deck around it, but I don't see it breaking the tournament scene wide open anytime soon. I've been wrong before, though...