Dominion Ruins (adding more hero levels)
I have been trying to beat Street 10 room 7 for 3 stars for a long time now and am getting infuriated with it. The concept is not hard to get, you have <1% chance of succeeding each try and you just have to repeat the process often enough. This system creates phenomenal variance where 20% of players can succeed within 20 tries and 5% of players will need over 250. This is incredibly unfair.
Before you had designed and released it I would have suggested making the final achievement to unlock after 10 successes with a 10% chance of success on each attempt. Now it has been released I suggest adding 10 more hero levels (no need for new equipment) so the players chance of success improves with each failure. Because as of right now it is an insidious lottery.