My complaint:
Spent $4B on chest no new card
Suggested solution:
Add a in app card store where you can trade duplicate cards for the exact card you need and or buy the exact card you need maybe do it for duplicates and coins like give the player an option of either or. Trade gray or white cards for gray or white cards and gold cards for gold cards based on the star level and level of rarity will tell you how many cards need traded for that card. Just a suggestion would love to know what you think