Yes I see it would be an effective counter but my main problem is trying to find a deck that this would be effective with.
My recommendations for decks would be along the lines of the following:
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Use plague, retrovirus & pandemonium for creature control. If they try to use creature control against you usually they'll hit a skeleton, and permanent control would often be wasted on bone wall or pillars instead of hitting valuable permanents like boneyard & chaos dice. They couldn't count on taking out you vultures while they're still small since they can't target, and indiscriminate killing is a bad idea against
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Use lycanthropes for offense and devourers & discord to slow your opponent down. Chaos dice will keep your opponent from taking out the lycans while they still only have 1 hp. If you want creature control go for pandemonium again.
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Use just enough
to be able to play the chaos dice when you need them. Cremate can provide some of the
quanta you need (since you'll be playing it before you play chaos dice you can still target it) use chaos dice to protect lava golems until they have enough time to grow. RoF and fire shield are both decent creature control that would get along fine with the dice.
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Similar to
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but substitute dragons for lava golems.
The main thing I think the card would be useful for is any of the decks you're thinking of that it wouldn't work with could be severely hampered by an opponent who played this card. Any of these sound like decent decks to you?
P.S. After the changes the vote count in crucible was reset to 0, so any supporters of this card out there need to re-vote.