Ok, so the card mini game, I've seen this happen before now, it takes one human error to lose the race for 1st place for the 100 gems and Arena Ring...
But the problem here is though who have excess of 10 6star cards don't technically play the mini game since if I remember KingK saying its more about strategy and card placement... Now I've been lucky to get my card drops 1 7 star and 4 6 star cards. Now those who have literally payed to get there cards wont be playing how it was meant to based on KingK's explanation on the Kong forum.
Now theres 3 ways to solve this and make the playing field fair for everyone.
1. Card exp % based attacks so someone with 60% cant fight someone with say 45%
2. The Winner of the previous week can still take part in the fights seeing as there is 2 badges, but his points for the wins aren't counted (to stop paying people with 60%+ constantly winning and farming the gems)
3. Apply a card strength cap of say 50 based on card star level so 10 5 star cards equals 50 deck strength, That will means again those who have brought there cards wont be able to farm it week after week for the 100gems.