All they need to do is give all played cards a flat damage increase across the board but give back the an added effect for each card similar to how the old system was. To keep it from being overpowered they just need to tone down the added effect to a fraction of what it used to be in the past. A modest 5% reduction in MP cost, a mere 3% increase in attack speed, a 5% movement speed boost, etc. nothing that really affects game play but it would add some extra flavor to the current card system. To keep people from fishing for specific cards just make it so any three cards played gives you the full divination effect without having to match certain cards anymore.