with it being a 'clan adventure' it could be a way too reward the top clans, like have the top 10 have an increased chance of epic and/or have rank 1 have a guaranteed rare/epic, just a thought.
This is just my opinion, but it sounds like you really don't like working hard to get something you want.
I'm quite happy working hard too earn things, it was merely a suggestion, sorry if it came across as anything else.