Compensation "idea"
I know it's official what Kabam will do to compensate for the error on the 7* pool. But what if instead of sending 1 exact copy of the crystal with the current pool, they send a special crystal, which would be the same as the crystals they are sending but instead of getting a champion every time you get 1 gold for every champion that was in the pool before the update but if you score a champion from the added ones you get that. So, you could either score 1 gold or a champion from the newly added ones. Obviously with the correct rates to get a new champion that you would have got in your crystal.
This way if you were going to get a new champion you get it and you keep your other pull from before but if you were going to get a champion from the old pool, you already did, so now you just get 1 gold and you don't get an unfair advantage.
Just some thoughts, don't even know if it's doable.