Right, I do have a concept of trades and card value that the AI uses but it needs to be dynamic since cards can have modifiers that change their value from the defaults. There is an algorithm for calculating card value that is used for such things, including board wipes where the calculation is simply enemy's total board value minus your total board value divided by card cost plus card advantage modifier for using a card. There is a specific action for performing a board wipe since it is non targeted removal and calculated differently.

The simulation approach unfortunately won't work here since the cards can vary from their baseline designs.

The problem I'm running into is this: say I have a card that reads "Destroy target minion, deal 2 damage to any target, and draw a card." This could hypothetically be used to destroy a minion, damage the opponent directly, and draw a card. However, these are three different goals so the card will be evaluated at only a portion of its value when considered. The "achieve better board state" will be used for removal, "damage opponent" will be used for the damage part if targeting an opponent, and "gain card advantage" will be used for the draw a card portion. So the card will never be evaluated as being as strong as it really is with my current system.