i just got a idea, i know it currently is not possible to use it like this and probably no one likes it anyway... actually i somewhat dont like it either =) but since i had the idea i thought i'd share it with you.
the idea came because it is somehow just not fun, beating the crap out of your enemy but loosing in the end just because he got one lucky card and you dont.
the effect cooldown would be a new feature to stop overpowered cards being overpowered and it would also add some more strategical thinking to the game.
what i mean with cooldown is, that any new card you get in your hand will be unuseable for a set period of turns.
how long a new card is unusable will be desided by its rarity and overpoweredness. so, common would be usable the instant you get it, uncommon would be off for one turn and rare for two turns.
cards like prince of thieves or order of the white lotus will get an extra +1 turn off, while weaker cards like manticore get a turn less off.
your starting hand does not have a cooldown.
if you steal a card, it will get an additional cooldown of 1 turn (additionally to the cooldown already set for a card).
the cooldown counter will be reduced by one at the end of enemy's turn.
an example: i just recieved prince of thieves after playing tribute (cooldown 3) the opponent black market it to his hand (cooldown 4) my turn, i do nothing (cd 3), enemy neither, i do nothing again (cd 2) enemy neither, i black market prince back to my hand (cd 3). and so on.
like this it is actually possible to never be able to play the card that is swiched all the time.
thats about it. i wonder how you think about haveing to wait till you can use that awesome card you just recieved instead of hitting your enemy where it hurts most the instant you can.