Did you ever wish your Tinker out was also a counterspell? Well, have I got a deal for you:
This card seems like a very reasonable variant on the bounce spells we already run in Vintage. You lose the ability to bounce non-creatures, but you gain the ability to do two things on top of having an out to Tinker / Show and Tell / Oath / Marit Lage creatures:
Offensively, you can counter spells that your opponent does not have the resources to re-cast this turn, like something they cast off of a Dark Ritual, something they tapped out for, or a Force they had to pitch their last blue card to cast; and
Defensively, you can use this to increase your storm count or make more Moar Biggar Monk Tokens like people used good ol' Arcane Denial. You can use it to rebuy and recast your Flusterstorm for BIGGER. You can save your own spells from being countered so you can cast them next turn.
Card is really cool, and I think it's absolutely playable. The trick is whether a deck really wants this particular toolbox of effects.
Now, why can't Wizards give us this level of toolbox awesomeness in cards that are not blue counterspells...?
EDIT: In addition to the above, this card has fun uses in Legacy. It punishes Miracles really hard, since it can counter a spell being cast as a Miracle and stuff it into their hand. It kills Angel tokens in a pinch, too. Against Abrupt Decay and Supreme Verdict, it at least delays the spell for a turn most of the time -- it's not actually countering the spell.