I'll try to use the plague card from death element as an example to help put things into perspective.
Plague costs 4
to put a single stack of poison on all opposing creatures.
To effect every ally creature and remain balanced, Anti-Venom would cost 4
. This would limit players to using Anti-Venom
when there's a lot of creatures already in play, as well as remove options for giving extra protection to some creatures while sacrificing others.
Improved Plague costs only 2
, but still applies only a single stack of poison.
Changing Potent Anti-Venom to reflect this while maintaining it's current cost would severely downgrade the card by my estimation.
Now, if you're still concerned about 2
being too great a cost to remove poison from a creature, please consider my next example. In the current game, the player of a life deck employs a giant frog for 2
and then enhances it with epinephrine for another 3
. Afterward, the opponent uses spine carapace. Without Anti-Venom, it is likely the player will be down 5
and 2-cards from his deck very shortly, with little damage done to show for it. With Potent Anti-Venom however,
the player has the option to lose 2
instead and get another turn of attacks out of their giant frog.
...I simply cannot see how reducing the cost of Anti-Venom further would be beneficial to the game. Honestly I'd rather leave Anti-venom out of the game than create a new imbalance from the various decks that would use it. I must consider those using the creature-poisoning and death decks as well as those countering them.
Of course, no card is completely perfect. If anyone can argue the value in lowering Anti-Venom's cost in a balanced way, based upon a more reasonable criticism than it simply 'seems' or 'sounds' too expensive, please do so.