As someone really unlucky, to make the game more “balanced” and less reliable on luck (but will still be) , i’d like to offer a solution to “unlucky” and “really lucky” players out there.
Lets say, you open 10 rare eggs and got 10 SE dupes. That is really frustrating knowing rare gems is hard to get for low-moderate level players. But how about the chance of getting the same monster rarity is decreased everytime you got them ?
For example, on rare eggs you got a SE. Then 60% chance for it becomes 55% for a SE next egg, and if you still got them, the next egg will have 50% of getting them and so on. When you finally get a legend, the chances are resetted and the chance of getting a legend is reduced to 35%.
However this can only work on rare eggs where there are only 2 variables. On regular eggs it will be harder to implement because there are 3 variables (epics, superepics, legendaries)
Hope this will do for “unlucky” players and make the game more “balanced”. Leave the dupes where they are. I will be Waiting for your response devs! 
Sorry for bad english