A couple of years ago a man widely considered as a top genius PR guru at Team 5 suggested that it was a good idea to hype and unveil an expansion, but then wait for a friggin' month to continue on with the card reveals. Team 5 never questioned his transcendent wisdom, not for a split second and decided to employ his PR tactics for as long as there's expansions to print.
Great concept in general but it is a horrible for 8 mana. In most cases, your opening hand should have early game minions (with some possible spells and such). By the time that you play this card, a copy of your opening hand would suck (because otherwise, agro and combo decks would killed you by now). This should of been 6 mana at the least.
If Mage gets a good, cheap board-clear, similar to Volcanic Potion, this might be ok. Otherwise, I see no point in it. You either want to keep cards in the opening hand that help you survive, or cards that give you the upper hand in the early game. If you want to survive, you need to find a moment to play this, if you care about tempo, you don't care about turn 8.
And whatever you have in mind, it is a gamble. At least to me it is. I know that all pros out there always get the same 4 cards in their opening hand, like Prince Keleseth and Wild Growth and such, but I can't preset my opening hand, so I might end up with cards that aren't worth copying, which would also make this card quite bad.
Of course, it's still too early to say this, but I am relatively sure that this will see no play.