The simplest bandaid fix would be to implement smart cards. If you're not targeting a party member when you hit play, a melee card goes to the closest melee>tank>ranged>healer who doesn't have a buff currently. Ranged cards would be ranged>healer>melee>tank.

Cards could still be placed on specific individuals by taking the time to target them.

This is a small enough change to be done in a patch. I don't see a full rework coming until the next expansion, unfortunately.